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1 .H0 "Discussion
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2 .P
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3 This main chapter discusses the practical work done in the mmh project.
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4 It is structured along the goals to achieve.
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5 The concrete work done
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6 is described in the examples of how the general goals were achieved.
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7 The discussion compares the current version of mmh with the state of
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8 nmh just before the mmh project started, i.e. Fall 2011.
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9 Current changes of nmh will be mentioned only as side notes.
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10 .\" XXX where do I discuss the parallel development of nmh?
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11
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12
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13
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14 .\" --------------------------------------------------------------
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15 .H1 "Streamlining
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16
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17 .P
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18 MH had been considered an all-in-one system for mail handling.
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19 The community around nmh has a similar understanding.
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20 In fundamental difference, mmh shall be a MUA only.
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21 I believe that the development of all-in-one mail systems is obsolete.
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22 Today, email is too complex to be fully covered by single projects.
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23 Such a project won't be able to excel in all aspects.
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24 Instead, the aspects of email should be covered my multiple projects,
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25 which then can be combined to form a complete system.
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26 Excellent implementations for the various aspects of email exist already.
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27 Just to name three examples: Postfix is a specialized MTA,
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28 Procmail is a specialized MDA, and Fetchmail is a specialized MRA.
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29 I believe that it is best to use such specialized tools instead of
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30 providing the same function again as a side-component in the project.
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31 .P
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32 Doing something well, requires to focus on a small set of specific aspects.
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33 Under the assumption that focused development produces better results
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34 in the particular area, specialized projects will be superior
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35 in their field of focus.
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36 Hence, all-in-one mail system projects \(en no matter if monolithic
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37 or modular \(en will never be the best choice in any of the fields.
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38 Even in providing the best consistent all-in-one system they are likely
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39 to be beaten by projects that focus only on integrating existing mail
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40 components to a homogeneous system.
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41 .P
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42 The limiting resource in Free Software community development
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43 is usually man power.
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44 If the development power is spread over a large development area,
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45 it becomes even more difficult to compete with the specialists in the
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46 various fields.
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47 The concrete situation for MH-based mail systems is even tougher,
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48 given the small and aged community, including both developers and users,
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49 it has.
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50 .P
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51 In consequence, I believe that the available development resources
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52 should focus on the point where MH is most unique.
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53 This is clearly the user interface \(en the MUA.
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54 Peripheral parts should be removed to streamline mmh for the MUA task.
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55
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56
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57 .H2 "Mail Transfer Facilities
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58 .P
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59 In contrast to nmh, which also provides mail submission and mail retrieval
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60 agents, mmh is a MUA only.
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61 This general difference initiated the development of mmh.
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62 Removing the mail transfer facilities had been the first work task
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63 in the mmh project.
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64 .P
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65 Focusing on one mail agent role only is motivated by Eric Allman's
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66 experience with Sendmail.
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67 He identified limiting Sendmail the MTA task had be one reason for
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68 its success:
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69 .[ [
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70 costales sendmail
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71 .], p. xviii]
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72 .QS
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73 Second, I limited myself to the routing function \(en
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74 I wouldn't write user agents or delivery back-ends.
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75 This was a departure of the dominant through of the time,
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76 in which routing logic, local delivery, and often the network code
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77 were incorporated directly into the user agents.
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78 .QE
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79 .P
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80 In mmh, the Mail Submission Agent (MSA) is called
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81 \fIMessage Transfer Service\fP (MTS).
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82 This facility, implemented by the
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83 .Pn post
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84 command, established network connections and spoke SMTP to submit
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85 messages for relay to the outside world.
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86 The changes in email demanded changes in this part of nmh too.
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87 Encryption and authentication for network connections
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88 needed to be supported, hence TLS and SASL were introduced into nmh.
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89 This added complexity to nmh without improving it in its core functions.
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90 Also, keeping up with recent developments in the field of
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91 mail transfer requires development power and specialists.
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92 In mmh this whole facility was simply cut off.
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93 .Ci f6aa95b724fd8c791164abe7ee5468bf5c34f226
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94 .Ci fecd5d34f65597a4dfa16aeabea7d74b191532c3
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95 .Ci 156d35f6425bea4c1ed3c4c79783dc613379c65b
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96 Instead, mmh depends on an external MSA.
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97 The only outgoing interface available to mmh is the
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98 .Pn sendmail
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99 command, which almost any MSA provides.
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100 If not, a wrapper program can be written.
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101 It must read the message from the standard input, extract the
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102 recipient addresses from the message header, and hand the message
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103 over to the MSA.
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104 For example, a wrapper script for qmail would be:
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105 .VS
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106 #!/bin/sh
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107 # ignore command line arguments
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108 exec qmail-inject
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109 VE
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110 The requirement to parse the recipient addresses out of the message header
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111 is likely to be removed in the future.
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112 Then mmh would give the recipient addresses as command line arguments.
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113 This appears to be the better interface.
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114 .\" XXX implement it
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115 .P
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116 To retrieve mail, the
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117 .Pn inc
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118 command acted as Mail Retrieval Agent (MRA).
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119 It established network connections
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120 and spoke POP3 to retrieve mail from remote servers.
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121 As with mail submission, the network connections required encryption and
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122 authentication, thus TLS and SASL were added.
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123 Support for message retrieval through IMAP will become necessary
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124 to be added soon, too, and likewise for any other changes in mail transfer.
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125 Not so for mmh because it has dropped the support for retrieving mail
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126 from remote locations.
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127 .Ci ab7b48411962d26439f92f35ed084d3d6275459c
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128 Instead, it depends on an external tool to cover this task.
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129 In mmh exist two paths for messages to enter mmh's mail storage:
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130 (1) Mail can be incorporated with
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131 .Pn inc
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132 from the system maildrop, or (2) with
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133 .Pn rcvstore
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134 by reading them, one at a time, from the standard input.
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135 .P
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136 With the removal of the MSA and MRA, mmh converted from an all-in-one
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137 mail system to being a MUA only.
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138 Now, of course, mmh depends on third-party software.
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139 An external MSA is required to transfer mail to the outside world;
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140 an external MRA is required to retrieve mail from remote machines.
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141 There exist excellent implementations of such software,
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142 which do this specific task likely better than the internal
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143 versions had done it.
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144 Also, the best suiting programs can be freely chosen.
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145 .P
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146 As it had already been possible to use an external MSA or MRA,
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147 why not keep the internal version for convenience?
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148 The question whether there is sense in having a fall-back pager in all
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149 the command line tools, for the cases when
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150 .Pn more
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151 or
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152 .Pn less
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153 aren't available, appears to be ridiculous.
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154 Of course, MSAs and MRAs are more complex than text pagers
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155 and not necessarily available but still the concept of orthogonal
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156 design holds: ``Write programs that do one thing and do it well.''
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157 .[
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158 mcilroy unix phil
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159 p. 53
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160 .]
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161 .[
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162 mcilroy bstj foreword
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163 .]
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164 Here, this part of the Unix philosophy was applied not only
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165 to the programs but to the project itself.
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166 In other words:
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167 ``Develop projects that focus on one thing and do it well.''
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168 Projects grown complex should be split for the same reasons programs grown
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169 complex should be split.
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170 If it is conceptionally more elegant to have the MSA and MRA as
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171 separate projects then they should be separated.
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172 This is the case here, in my opinion.
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173 The RFCs propose this separation by clearly distinguishing the different
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174 mail handling tasks.
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175 .[
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176 rfc 821
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177 .]
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178 The small interfaces between the mail agents support the separation.
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179 .P
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180 In the beginning, email had been small and simple.
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181 At that time,
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182 .Pn /bin/mail
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183 had covered anything there was to email and still had been small
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184 and simple.
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185 Later, the essential complexity of email increased.
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186 (Essential complexity is the complexity defined by the problem itself.\0
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187 .[[
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188 brooks no silver bullet
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189 .]])
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190 Email systems reacted to this change: They grew.
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191 RFCs started to introduce the concept of mail agents to separate the
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192 various tasks because they became more extensive and new tasks appeared.
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193 As the mail systems grew even more, parts were split off.
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194 In nmh, for instance, the POP server, which was included in the original
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195 MH, was removed.
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196 Now is the time to go one step further and split the MSA and MRA off, too.
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197 Not only does this decrease the code size of the project,
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198 but, more important, it unburdens mmh of the whole field of
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199 message transfer with all its implications for the project.
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200 There is no more need to concern with changes in network transfer.
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201 This independence is received by depending on an external program
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202 that covers the field.
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203 Today, this is a reasonable exchange.
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204 .P
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205 Functionality can be added in three different ways:
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206 .BU
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207 Implementing the function originally in the project.
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208 .BU
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209 Depending on a library that provides the function.
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210 .BU
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211 Depending on a program that provides the function.
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212 .P
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213 Whereas adding the function originally to the project increases the
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214 code size most and requires most maintenance and development work,
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215 it makes the project most independent of other software.
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216 Using libraries or external programs require less maintenance work
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217 but introduces dependencies on external software.
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218 Programs have the smallest interfaces and provide the best separation
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219 but possibly limit the information exchange.
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220 External libraries are stronger connected than external programs,
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221 thus information can be exchanged more flexible.
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222 Adding code to a project increases maintenance work.
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223 .\" XXX ref
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224 Implementing complex functions originally in the project adds
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225 a lot of code.
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226 This should be avoided if possible.
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227 Hence, the dependencies only change in kind, not in their existence.
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228 In mmh, library dependencies on
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229 .Pn libsasl2
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230 and
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231 .Pn libcrypto /\c
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232 .Pn libssl
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233 were treated against program dependencies on an MSA and an MRA.
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234 This also meant treating build-time dependencies against run-time
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235 dependencies.
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236 Besides program dependencies providing the stronger separation
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237 and being more flexible, they also allowed
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238 over 6\|000 lines of code to be removed from mmh.
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239 This made mmh's code base about 12\|% smaller.
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240 Reducing the project's code size by such an amount without actually
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241 losing functionality is a convincing argument.
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242 Actually, as external MSAs and MRAs are likely superior to the
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243 project's internal versions, the common user even gains functionality.
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244 .P
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245 Users of MH should not have problems to set up an external MSA and MRA.
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246 Also, the popular MSAs and MRAs have large communities and a lot
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247 of documentation available.
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248 Choices for MSAs range from full-featured MTAs like
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249 .I Postfix
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250 over mid-size MTAs like
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251 .I masqmail
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252 and
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253 .I dma
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254 to small forwarders like
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255 .I ssmtp
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256 and
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257 .I nullmailer .
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258 Choices for MRAs include
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259 .I fetchmail ,
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260 .I getmail ,
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261 .I mpop
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262 and
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263 .I fdm .
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264
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265
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266 .H2 "Non-MUA Tools
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267 .P
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268 One goal of mmh is to remove the tools that are not part of the MUA's task.
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269 Further more, any tools that don't improve the MUA's job significantly
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270 should be removed.
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271 Loosely related and rarely used tools distract from the lean appearance.
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272 They require maintenance work without adding much to the core task.
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273 By removing these tools, the project shall become more streamlined
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274 and focused.
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275 In mmh the following tools are not available anymore:
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276 .BU
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277 .Pn conflict
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278 was removed
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279 .Ci 8b235097cbd11d728c07b966cf131aa7133ce5a9
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280 because it is a mail system maintenance tool that is not MUA-related.
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281 It even checked
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282 .Fn /etc/passwd
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283 and
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284 .Fn /etc/group
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285 for consistency, which is completely unrelated to email.
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286 A tool like
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287 .Pn conflict
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288 is surely useful, but it should not be shipped with mmh.
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289 .\" XXX historic reasons?
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290 .BU
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291 .Pn rcvtty
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292 was removed
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293 .Ci 14767c94b3827be7c867196467ed7aea5f6f49b0
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294 because its use case of writing to the user's terminal
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295 on receiving of mail is obsolete.
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296 If users like to be informed of new mail, the shell's
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297 .Ev MAILPATH
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298 variable or graphical notifications are technically more appealing.
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299 Writing directly to terminals is hardly ever wanted today.
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300 If though one wants to have it this way, the standard tool
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301 .Pn write
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302 can be used in a way similar to:
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303 .VS
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304 scan -file - | write `id -un`
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305 VE
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306 .BU
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307 .Pn viamail
|
|
meillo@87
|
308 was removed
|
|
meillo@87
|
309 .Ci eda72d6a7a7c20ff123043fb7f19c509ea01f932
|
|
meillo@87
|
310 when the new attachment system was activated, because
|
|
meillo@58
|
311 .Pn forw
|
|
meillo@76
|
312 could then cover the task itself.
|
|
meillo@62
|
313 The program
|
|
meillo@58
|
314 .Pn sendfiles
|
|
meillo@62
|
315 was rewritten as a shell script wrapper around
|
|
meillo@58
|
316 .Pn forw .
|
|
meillo@76
|
317 .Ci 0e82199cf3c991a173e0ac8aa776efdb3ded61e6
|
|
meillo@62
|
318 .BU
|
|
meillo@58
|
319 .Pn msgchk
|
|
meillo@87
|
320 was removed
|
|
meillo@87
|
321 .Ci bb9360ead7eb7a3fedcce2eeedfc660014e41dbe ,
|
|
meillo@87
|
322 because it lost its use case when POP support was removed.
|
|
meillo@76
|
323 A call to
|
|
meillo@58
|
324 .Pn msgchk
|
|
meillo@87
|
325 provided hardly more information than:
|
|
meillo@82
|
326 .VS
|
|
meillo@58
|
327 ls -l /var/mail/meillo
|
|
meillo@82
|
328 VE
|
|
meillo@100
|
329 It did distinguish between old and new mail, but
|
|
meillo@100
|
330 this detail information can be retrieved with
|
|
meillo@76
|
331 .Pn stat (1),
|
|
meillo@62
|
332 too.
|
|
meillo@100
|
333 A small shell script could be written to print the information
|
|
meillo@76
|
334 in a similar way, if truly necessary.
|
|
meillo@76
|
335 As mmh's
|
|
meillo@76
|
336 .Pn inc
|
|
meillo@87
|
337 only incorporates mail from the user's local maildrop,
|
|
meillo@62
|
338 and thus no data transfers over slow networks are involved,
|
|
meillo@76
|
339 there's hardly any need to check for new mail before incorporating it.
|
|
meillo@62
|
340 .BU
|
|
meillo@58
|
341 .Pn msh
|
|
meillo@87
|
342 was removed
|
|
meillo@76
|
343 .Ci 916690191222433a6923a4be54b0d8f6ac01bd02
|
|
meillo@87
|
344 because the tool was in conflict with the philosophy of MH.
|
|
meillo@76
|
345 It provided an interactive shell to access the features of MH,
|
|
meillo@76
|
346 but it wasn't just a shell, tailored to the needs of mail handling.
|
|
meillo@76
|
347 Instead it was one large program that had several MH tools built in.
|
|
meillo@76
|
348 This conflicts with the major feature of MH of being a tool chest.
|
|
meillo@76
|
349 .Pn msh 's
|
|
meillo@76
|
350 main use case had been accessing Bulletin Boards, which have seized to
|
|
meillo@62
|
351 be popular.
|
|
meillo@62
|
352 .P
|
|
meillo@62
|
353 Removing
|
|
meillo@58
|
354 .Pn msh ,
|
|
meillo@76
|
355 together with the truly archaic code relicts
|
|
meillo@58
|
356 .Pn vmh
|
|
meillo@58
|
357 and
|
|
meillo@58
|
358 .Pn wmh ,
|
|
meillo@62
|
359 saved more than 7\|000 lines of C code \(en
|
|
meillo@66
|
360 about 15\|% of the project's original source code amount.
|
|
meillo@100
|
361 Having less code \(en with equal readability, of course \(en
|
|
meillo@76
|
362 for the same functionality is an advantage.
|
|
meillo@63
|
363 Less code means less bugs and less maintenance work.
|
|
meillo@76
|
364 As
|
|
meillo@63
|
365 .Pn rcvtty
|
|
meillo@63
|
366 and
|
|
meillo@63
|
367 .Pn msgchk
|
|
meillo@87
|
368 are assumed to be rarely used and can be implemented in different ways,
|
|
meillo@87
|
369 why should one keep them?
|
|
meillo@125
|
370 Removing them streamlines mmh.
|
|
meillo@63
|
371 .Pn viamail 's
|
|
meillo@63
|
372 use case is now partly obsolete and partly covered by
|
|
meillo@63
|
373 .Pn forw ,
|
|
meillo@76
|
374 hence there's no reason to still maintain it.
|
|
meillo@63
|
375 .Pn conflict
|
|
meillo@76
|
376 is not related to the mail client, and
|
|
meillo@63
|
377 .Pn msh
|
|
meillo@63
|
378 conflicts with the basic concept of MH.
|
|
meillo@76
|
379 Theses two tools might still be useful, but they should not be part of mmh.
|
|
meillo@63
|
380 .P
|
|
meillo@76
|
381 Finally, there's
|
|
meillo@76
|
382 .Pn slocal .
|
|
meillo@76
|
383 .Pn slocal
|
|
meillo@76
|
384 is an MDA and thus not directly MUA-related.
|
|
meillo@100
|
385 It should be removed from mmh, because including it conflicts with
|
|
meillo@100
|
386 the idea that mmh is a MUA only.
|
|
meillo@100
|
387 .Pn slocal
|
|
meillo@100
|
388 should rather become a separate project.
|
|
meillo@87
|
389 However,
|
|
meillo@76
|
390 .Pn slocal
|
|
meillo@76
|
391 provides rule-based processing of messages, like filing them into
|
|
meillo@76
|
392 different folders, which is otherwise not available in mmh.
|
|
meillo@87
|
393 Although
|
|
meillo@76
|
394 .Pn slocal
|
|
meillo@87
|
395 does neither pull in dependencies nor does it include a separate
|
|
meillo@100
|
396 technical area (cf. Sec. XXX), still,
|
|
meillo@100
|
397 it accounts for about 1\|000 lines of code that need to be maintained.
|
|
meillo@76
|
398 As
|
|
meillo@76
|
399 .Pn slocal
|
|
meillo@76
|
400 is almost self-standing, it should be split off into a separate project.
|
|
meillo@76
|
401 This would cut the strong connection between the MUA mmh and the MDA
|
|
meillo@76
|
402 .Pn slocal .
|
|
meillo@87
|
403 For anyone not using MH,
|
|
meillo@87
|
404 .Pn slocal
|
|
meillo@87
|
405 would become yet another independent MDA, like
|
|
meillo@87
|
406 .I procmail .
|
|
meillo@100
|
407 Then
|
|
meillo@87
|
408 .Pn slocal
|
|
meillo@100
|
409 could be installed without the complete MH system.
|
|
meillo@76
|
410 Likewise, mmh users could decide to use
|
|
meillo@76
|
411 .I procmail
|
|
meillo@87
|
412 without having a second, unused MDA,
|
|
meillo@87
|
413 .Pn slocal ,
|
|
meillo@76
|
414 installed.
|
|
meillo@100
|
415 That appears to be conceptionally the best solution.
|
|
meillo@76
|
416 Yet,
|
|
meillo@76
|
417 .Pn slocal
|
|
meillo@87
|
418 is not split off.
|
|
meillo@100
|
419 I defer the decision over
|
|
meillo@78
|
420 .Pn slocal
|
|
meillo@100
|
421 in need for deeper investigation.
|
|
meillo@100
|
422 In the meanwhile, it remains part of mmh.
|
|
meillo@100
|
423 That does not hurt because
|
|
meillo@100
|
424 .Pn slocal
|
|
meillo@100
|
425 is unrelated to the rest of the project.
|
|
meillo@0
|
426
|
|
meillo@58
|
427
|
|
meillo@133
|
428
|
|
meillo@133
|
429 .H2 "\fLshow\fP and \fPmhshow\fP
|
|
meillo@131
|
430 .P
|
|
meillo@133
|
431 Since the very beginning, already in the first concept paper,
|
|
meillo@58
|
432 .Pn show
|
|
meillo@62
|
433 had been MH's message display program.
|
|
meillo@58
|
434 .Pn show
|
|
meillo@76
|
435 mapped message numbers and sequences to files and invoked
|
|
meillo@58
|
436 .Pn mhl
|
|
meillo@89
|
437 to have the files formatted.
|
|
meillo@88
|
438 With MIME, this approach wasn't sufficient anymore.
|
|
meillo@100
|
439 MIME messages can consist of multiple parts. Some parts are not
|
|
meillo@100
|
440 directly displayable and text content might be encoded in
|
|
meillo@58
|
441 foreign charsets.
|
|
meillo@58
|
442 .Pn show 's
|
|
meillo@76
|
443 understanding of messages and
|
|
meillo@58
|
444 .Pn mhl 's
|
|
meillo@88
|
445 display capabilities couldn't cope with the task any longer.
|
|
meillo@62
|
446 .P
|
|
meillo@88
|
447 Instead of extending these tools, additional tools were written from
|
|
meillo@88
|
448 scratch and added to the MH tool chest.
|
|
meillo@88
|
449 Doing so is encouraged by the tool chest approach.
|
|
meillo@88
|
450 Modular design is a great advantage for extending a system,
|
|
meillo@88
|
451 as new tools can be added without interfering with existing ones.
|
|
meillo@62
|
452 First, the new MIME features were added in form of the single program
|
|
meillo@58
|
453 .Pn mhn .
|
|
meillo@58
|
454 The command
|
|
meillo@82
|
455 .Cl "mhn -show 42
|
|
meillo@58
|
456 would show the MIME message numbered 42.
|
|
meillo@58
|
457 With the 1.0 release of nmh in February 1999, Richard Coleman finished
|
|
meillo@58
|
458 the split of
|
|
meillo@58
|
459 .Pn mhn
|
|
meillo@88
|
460 into a set of specialized tools, which together covered the
|
|
meillo@88
|
461 multiple aspects of MIME.
|
|
meillo@88
|
462 One of them was
|
|
meillo@69
|
463 .Pn mhshow ,
|
|
meillo@88
|
464 which replaced
|
|
meillo@88
|
465 .Cl "mhn -show" .
|
|
meillo@88
|
466 It was capable of displaying MIME messages appropriately.
|
|
meillo@62
|
467 .P
|
|
meillo@88
|
468 From then on, two message display tools were part of nmh,
|
|
meillo@76
|
469 .Pn show
|
|
meillo@76
|
470 and
|
|
meillo@76
|
471 .Pn mhshow .
|
|
meillo@88
|
472 To ease the life of users,
|
|
meillo@69
|
473 .Pn show
|
|
meillo@69
|
474 was extended to automatically hand the job over to
|
|
meillo@69
|
475 .Pn mhshow
|
|
meillo@69
|
476 if displaying the message would be beyond
|
|
meillo@69
|
477 .Pn show 's
|
|
meillo@69
|
478 abilities.
|
|
meillo@88
|
479 In consequence, the user would simply invoke
|
|
meillo@69
|
480 .Pn show
|
|
meillo@69
|
481 (possibly through
|
|
meillo@69
|
482 .Pn next
|
|
meillo@69
|
483 or
|
|
meillo@69
|
484 .Pn prev )
|
|
meillo@69
|
485 and get the message printed with either
|
|
meillo@69
|
486 .Pn show
|
|
meillo@69
|
487 or
|
|
meillo@69
|
488 .Pn mhshow ,
|
|
meillo@69
|
489 whatever was more appropriate.
|
|
meillo@69
|
490 .P
|
|
meillo@69
|
491 Having two similar tools for essentially the same task is redundant.
|
|
meillo@88
|
492 Usually,
|
|
meillo@88
|
493 users wouldn't distinguish between
|
|
meillo@88
|
494 .Pn show
|
|
meillo@88
|
495 and
|
|
meillo@88
|
496 .Pn mhshow
|
|
meillo@88
|
497 in their daily mail reading.
|
|
meillo@88
|
498 Having two separate display programs was therefore mainly unnecessary
|
|
meillo@88
|
499 from a user's point of view.
|
|
meillo@88
|
500 Besides, the development of both programs needed to be in sync,
|
|
meillo@76
|
501 to ensure that the programs behaved in a similar way,
|
|
meillo@76
|
502 because they were used like a single tool.
|
|
meillo@76
|
503 Different behavior would have surprised the user.
|
|
meillo@69
|
504 .P
|
|
meillo@69
|
505 Today, non-MIME messages are rather seen to be a special case of
|
|
meillo@100
|
506 MIME messages, although it is the other way round.
|
|
meillo@69
|
507 As
|
|
meillo@69
|
508 .Pn mhshow
|
|
meillo@88
|
509 had already be able to display non-MIME messages, it appeared natural
|
|
meillo@69
|
510 to drop
|
|
meillo@69
|
511 .Pn show
|
|
meillo@69
|
512 in favor of using
|
|
meillo@69
|
513 .Pn mhshow
|
|
meillo@69
|
514 exclusively.
|
|
meillo@88
|
515 .Ci 4c1efddfd499300c7e74263e57d8aa137e84c853
|
|
meillo@88
|
516 Removing
|
|
meillo@88
|
517 .Pn show
|
|
meillo@88
|
518 is no loss in function, because functionally
|
|
meillo@88
|
519 .Pn mhshow
|
|
meillo@88
|
520 covers it completely.
|
|
meillo@88
|
521 The old behavior of
|
|
meillo@88
|
522 .Pn show
|
|
meillo@88
|
523 can still be emulated with the simple command line:
|
|
meillo@88
|
524 .VS
|
|
meillo@88
|
525 mhl `mhpath c`
|
|
meillo@88
|
526 VE
|
|
meillo@88
|
527 .P
|
|
meillo@76
|
528 For convenience,
|
|
meillo@76
|
529 .Pn mhshow
|
|
meillo@88
|
530 was renamed to
|
|
meillo@88
|
531 .Pn show
|
|
meillo@88
|
532 after
|
|
meillo@88
|
533 .Pn show
|
|
meillo@88
|
534 was gone.
|
|
meillo@88
|
535 It is clear that such a rename may confuse future developers when
|
|
meillo@88
|
536 trying to understand the history.
|
|
meillo@88
|
537 Nevertheless, I consider the convenience on the user's side,
|
|
meillo@88
|
538 to call
|
|
meillo@88
|
539 .Pn show
|
|
meillo@88
|
540 when they want a message to be displayed, to outweigh the inconvenience
|
|
meillo@88
|
541 on the developer's side when understanding the project history.
|
|
meillo@69
|
542 .P
|
|
meillo@88
|
543 To prepare for the transition,
|
|
meillo@69
|
544 .Pn mhshow
|
|
meillo@69
|
545 was reworked to behave more like
|
|
meillo@69
|
546 .Pn show
|
|
meillo@69
|
547 first.
|
|
meillo@88
|
548 (cf. Sec. XXX)
|
|
meillo@88
|
549 Once the tools behaved more alike, the replacing appeared to be
|
|
meillo@88
|
550 even more natural.
|
|
meillo@88
|
551 Today, mmh's new
|
|
meillo@69
|
552 .Pn show
|
|
meillo@88
|
553 became the one single message display program again, with the difference
|
|
meillo@88
|
554 that today it handles MIME messages as well as non-MIME messages.
|
|
meillo@88
|
555 The outcome of the transition is one program less to maintain,
|
|
meillo@88
|
556 no second display program for users to deal with,
|
|
meillo@88
|
557 and less system complexity.
|
|
meillo@69
|
558 .P
|
|
meillo@88
|
559 Still, removing the old
|
|
meillo@69
|
560 .Pn show
|
|
meillo@88
|
561 hurts in one regard: It had been such a simple program.
|
|
meillo@88
|
562 Its lean elegance is missing to the new
|
|
meillo@69
|
563 .Pn show .
|
|
meillo@88
|
564 But there is no chance;
|
|
meillo@88
|
565 supporting MIME demands for higher essential complexity.
|
|
meillo@58
|
566
|
|
meillo@58
|
567
|
|
meillo@133
|
568 .H2 "Scan Listings
|
|
meillo@131
|
569 .P
|
|
meillo@131
|
570 FIXME XXX
|
|
meillo@131
|
571
|
|
meillo@131
|
572 .P
|
|
meillo@131
|
573 commit c20e315f9fb9f0f0955749726dbf4fd897cd9f48
|
|
meillo@131
|
574 Author: markus schnalke <meillo@marmaro.de>
|
|
meillo@131
|
575 Date: Fri Dec 9 21:56:44 2011 +0100
|
|
meillo@131
|
576
|
|
meillo@131
|
577 Adjusted the default scan listing: remove the body preview
|
|
meillo@131
|
578 The original listing is still available as etc/scan.nmh
|
|
meillo@131
|
579
|
|
meillo@131
|
580 commit 70b2643e0da8485174480c644ad9785c84f5bff4
|
|
meillo@131
|
581 Author: markus schnalke <meillo@marmaro.de>
|
|
meillo@131
|
582 Date: Mon Jan 30 16:16:26 2012 +0100
|
|
meillo@131
|
583
|
|
meillo@131
|
584 Scan listings shall not contain body content. Hence, removed this feature.
|
|
meillo@131
|
585 Scan listings shall operator on message headers and non-message information
|
|
meillo@131
|
586 only. Displaying the beginning of the body complicates everything too much.
|
|
meillo@131
|
587 That's no surprise, because it's something completely different. If you
|
|
meillo@131
|
588 want to examine the body, then use show(1)/mhshow(1).
|
|
meillo@131
|
589 Changed the default scan formats accordingly.
|
|
meillo@131
|
590
|
|
meillo@131
|
591
|
|
meillo@131
|
592
|
|
meillo@133
|
593
|
|
meillo@100
|
594 .H2 "Configure Options
|
|
meillo@58
|
595 .P
|
|
meillo@76
|
596 Customization is a double-edged sword.
|
|
meillo@76
|
597 It allows better suiting setups, but not for free.
|
|
meillo@76
|
598 There is the cost of code complexity to be able to customize.
|
|
meillo@76
|
599 There is the cost of less tested setups, because there are
|
|
meillo@72
|
600 more possible setups and especially corner-cases.
|
|
meillo@76
|
601 And, there is the cost of choice itself.
|
|
meillo@76
|
602 The code complexity directly affects the developers.
|
|
meillo@72
|
603 Less tested code affects both, users and developers.
|
|
meillo@76
|
604 The problem of choice affects the users, for once by having to
|
|
meillo@100
|
605 choose, but also by more complex interfaces that require more documentation.
|
|
meillo@72
|
606 Whenever options add little advantages, they should be considered for
|
|
meillo@72
|
607 removal.
|
|
meillo@72
|
608 I have reduced the number of project-specific configure options from
|
|
meillo@72
|
609 fifteen to three.
|
|
meillo@74
|
610
|
|
meillo@76
|
611 .U3 "Mail Transfer Facilities
|
|
meillo@74
|
612 .P
|
|
meillo@85
|
613 With the removal of the mail transfer facilities five configure
|
|
meillo@85
|
614 options vanished:
|
|
meillo@85
|
615 .P
|
|
meillo@85
|
616 The switches
|
|
meillo@85
|
617 .Sw --with-tls
|
|
meillo@85
|
618 and
|
|
meillo@85
|
619 .Sw --with-cyrus-sasl
|
|
meillo@89
|
620 had activated the support for transfer encryption and authentication.
|
|
meillo@85
|
621 This is not needed anymore.
|
|
meillo@85
|
622 .Ci fecd5d34f65597a4dfa16aeabea7d74b191532c3
|
|
meillo@85
|
623 .Ci 156d35f6425bea4c1ed3c4c79783dc613379c65b
|
|
meillo@85
|
624 .P
|
|
meillo@85
|
625 The configure switch
|
|
meillo@85
|
626 .Sw --enable-pop
|
|
meillo@85
|
627 activated the message retrieval facility.
|
|
meillo@85
|
628 The code area that would be conditionally compiled in for TLS and SASL
|
|
meillo@85
|
629 support had been small.
|
|
meillo@85
|
630 The conditionally compiled code area for POP support had been much larger.
|
|
meillo@85
|
631 Whereas the code base changes would only slightly change on toggling
|
|
meillo@85
|
632 TLS or SASL support, it changed much on toggling POP support.
|
|
meillo@85
|
633 The changes in the code base could hardly be overviewed.
|
|
meillo@85
|
634 By having POP support togglable a second code base had been created,
|
|
meillo@85
|
635 one that needed to be tested.
|
|
meillo@85
|
636 This situation is basically similar for the conditional TLS and SASL
|
|
meillo@85
|
637 code, but there the changes are minor and can yet be overviewed.
|
|
meillo@85
|
638 Still, conditional compilation of a code base creates variations
|
|
meillo@85
|
639 of the original program.
|
|
meillo@85
|
640 More variations require more testing and maintenance work.
|
|
meillo@85
|
641 .P
|
|
meillo@85
|
642 Two other options only specified default configuration values:
|
|
meillo@100
|
643 .Sw --with-mts
|
|
meillo@100
|
644 defined the default transport service, either
|
|
meillo@100
|
645 .Ar smtp
|
|
meillo@100
|
646 or
|
|
meillo@100
|
647 .Ar sendmail .
|
|
meillo@85
|
648 In mmh this fixed to
|
|
meillo@85
|
649 .Ar sendmail .
|
|
meillo@85
|
650 .Ci f6aa95b724fd8c791164abe7ee5468bf5c34f226
|
|
meillo@85
|
651 With
|
|
meillo@100
|
652 .Sw --with-smtpservers
|
|
meillo@85
|
653 default SMTP servers for the
|
|
meillo@85
|
654 .Ar smtp
|
|
meillo@85
|
655 transport service could be specified.
|
|
meillo@72
|
656 .Ci 128545e06224233b7e91fc4c83f8830252fe16c9
|
|
meillo@85
|
657 Both of them became irrelevant.
|
|
meillo@72
|
658
|
|
meillo@74
|
659 .U3 "Backup Prefix
|
|
meillo@74
|
660 .P
|
|
meillo@76
|
661 The backup prefix is the string that was prepended to message
|
|
meillo@76
|
662 filenames to tag them as deleted.
|
|
meillo@76
|
663 By default it had been the comma character `\f(CW,\fP'.
|
|
meillo@78
|
664 In July 2000, Kimmo Suominen introduced
|
|
meillo@78
|
665 the configure option
|
|
meillo@78
|
666 .Sw --with-hash-backup
|
|
meillo@78
|
667 to change the default to the hash symbol `\f(CW#\fP'.
|
|
meillo@78
|
668 The choice was probably personal preference, because first, the
|
|
meillo@78
|
669 option was named
|
|
meillo@78
|
670 .Sw --with-backup-prefix.
|
|
meillo@78
|
671 and had the prefix symbol as argument.
|
|
meillo@100
|
672 But giving the hash symbol as argument caused too many problems
|
|
meillo@100
|
673 for Autoconf,
|
|
meillo@100
|
674 thus the option was limited to use the hash symbol as the default prefix.
|
|
meillo@100
|
675 This supports the assumption, that the choice for the hash was
|
|
meillo@100
|
676 personal preference only.
|
|
meillo@100
|
677 Being related or not, words that start with the hash symbol
|
|
meillo@78
|
678 introduce a comment in the Unix shell.
|
|
meillo@72
|
679 Thus, the command line
|
|
meillo@72
|
680 .Cl "rm #13 #15
|
|
meillo@72
|
681 calls
|
|
meillo@72
|
682 .Pn rm
|
|
meillo@72
|
683 without arguments because the first hash symbol starts the comment
|
|
meillo@72
|
684 that reaches until the end of the line.
|
|
meillo@72
|
685 To delete the backup files,
|
|
meillo@72
|
686 .Cl "rm ./#13 ./#15"
|
|
meillo@72
|
687 needs to be used.
|
|
meillo@100
|
688 Using the hash as backup prefix can be seen as a precaution against
|
|
meillo@78
|
689 data loss.
|
|
meillo@78
|
690 .P
|
|
meillo@72
|
691 I removed the configure option but added the profile entry
|
|
meillo@72
|
692 .Pe backup-prefix ,
|
|
meillo@72
|
693 which allows to specify an arbitrary string as backup prefix.
|
|
meillo@72
|
694 .Ci 6c40d481d661d532dd527eaf34cebb6d3f8ed086
|
|
meillo@76
|
695 Profile entries are the common method to change mmh's behavior.
|
|
meillo@76
|
696 This change did not remove the choice but moved it to a location where
|
|
meillo@72
|
697 it suited better.
|
|
meillo@76
|
698 .P
|
|
meillo@78
|
699 Eventually, however, the new trash folder concept
|
|
meillo@78
|
700 .Cf "Sec. XXX
|
|
meillo@78
|
701 obsoleted the concept of the backup prefix completely.
|
|
meillo@78
|
702 .Ci 8edc5aaf86f9f77124664f6801bc6c6cdf258173
|
|
meillo@133
|
703 .Ci ca0b3e830b86700d9e5e31b1784de2bdcaf58fc5
|
|
meillo@133
|
704
|
|
meillo@76
|
705
|
|
meillo@76
|
706 .U3 "Editor and Pager
|
|
meillo@74
|
707 .P
|
|
meillo@74
|
708 The two configure options
|
|
meillo@74
|
709 .CW --with-editor=EDITOR
|
|
meillo@74
|
710 .CW --with-pager=PAGER
|
|
meillo@74
|
711 were used to specify the default editor and pager at configure time.
|
|
meillo@109
|
712 Doing so at configure time made sense in the eighties,
|
|
meillo@76
|
713 when the set of available editors and pagers varied much across
|
|
meillo@76
|
714 different systems.
|
|
meillo@89
|
715 Today, the situation is more homogeneous.
|
|
meillo@74
|
716 The programs
|
|
meillo@74
|
717 .Pn vi
|
|
meillo@74
|
718 and
|
|
meillo@74
|
719 .Pn more
|
|
meillo@76
|
720 can be expected to be available on every Unix system,
|
|
meillo@74
|
721 as they are specified by POSIX since two decades.
|
|
meillo@74
|
722 (The specifications for
|
|
meillo@74
|
723 .Pn vi
|
|
meillo@74
|
724 and
|
|
meillo@74
|
725 .Pn more
|
|
meillo@74
|
726 appeared in
|
|
meillo@74
|
727 .[
|
|
meillo@74
|
728 posix 1987
|
|
meillo@74
|
729 .]
|
|
meillo@74
|
730 and,
|
|
meillo@74
|
731 .[
|
|
meillo@74
|
732 posix 1992
|
|
meillo@74
|
733 .]
|
|
meillo@74
|
734 respectively.)
|
|
meillo@74
|
735 As a first step, these two tools were hard-coded as defaults.
|
|
meillo@74
|
736 .Ci 5d43a99db70c12a673028c7758c20cbe3e13ef5f
|
|
meillo@74
|
737 Not changed were the
|
|
meillo@74
|
738 .Pe editor
|
|
meillo@74
|
739 and
|
|
meillo@74
|
740 .Pe moreproc
|
|
meillo@76
|
741 profile entries, which allowed the user to override the system defaults.
|
|
meillo@74
|
742 Later, the concept was reworked to respect the standard environment
|
|
meillo@74
|
743 variables
|
|
meillo@74
|
744 .Ev VISUAL
|
|
meillo@74
|
745 and
|
|
meillo@74
|
746 .Ev PAGER
|
|
meillo@76
|
747 if they are set.
|
|
meillo@74
|
748 Today, mmh determines the editor to use in the following order,
|
|
meillo@74
|
749 taking the first available and non-empty item:
|
|
meillo@74
|
750 .IP (1)
|
|
meillo@74
|
751 Environment variable
|
|
meillo@74
|
752 .Ev MMHEDITOR
|
|
meillo@74
|
753 .IP (2)
|
|
meillo@74
|
754 Profile entry
|
|
meillo@74
|
755 .Pe Editor
|
|
meillo@74
|
756 .IP (3)
|
|
meillo@74
|
757 Environment variable
|
|
meillo@74
|
758 .Ev VISUAL
|
|
meillo@74
|
759 .IP (4)
|
|
meillo@74
|
760 Environment variable
|
|
meillo@74
|
761 .Ev EDITOR
|
|
meillo@74
|
762 .IP (5)
|
|
meillo@74
|
763 Command
|
|
meillo@74
|
764 .Pn vi .
|
|
meillo@74
|
765 .P
|
|
meillo@76
|
766 .Ci f85f4b7ae62e3d05a945dcd46ead51f0a2a89a9b
|
|
meillo@76
|
767 .P
|
|
meillo@89
|
768 The pager to use is determined in a similar order,
|
|
meillo@74
|
769 also taking the first available and non-empty item:
|
|
meillo@74
|
770 .IP (1)
|
|
meillo@74
|
771 Environment variable
|
|
meillo@74
|
772 .Ev MMHPAGER
|
|
meillo@74
|
773 .IP (2)
|
|
meillo@74
|
774 Profile entry
|
|
meillo@74
|
775 .Pe Pager
|
|
meillo@74
|
776 (replaces
|
|
meillo@74
|
777 .Pe moreproc )
|
|
meillo@74
|
778 .IP (3)
|
|
meillo@74
|
779 Environment variable
|
|
meillo@74
|
780 .Ev PAGER
|
|
meillo@74
|
781 .IP (4)
|
|
meillo@74
|
782 Command
|
|
meillo@74
|
783 .Pn more .
|
|
meillo@74
|
784 .P
|
|
meillo@74
|
785 .Ci 0c4214ea2aec6497d0d67b436bbee9bc1d225f1e
|
|
meillo@74
|
786 .P
|
|
meillo@76
|
787 By respecting the
|
|
meillo@74
|
788 .Ev VISUAL /\c
|
|
meillo@74
|
789 .Ev EDITOR
|
|
meillo@74
|
790 and
|
|
meillo@74
|
791 .Ev PAGER
|
|
meillo@76
|
792 environment variables,
|
|
meillo@76
|
793 the new behavior confirms better to the common style on Unix systems.
|
|
meillo@76
|
794 Additionally, the new approach is more uniform and clearer to users.
|
|
meillo@72
|
795
|
|
meillo@72
|
796
|
|
meillo@76
|
797 .U3 "ndbm
|
|
meillo@72
|
798 .P
|
|
meillo@74
|
799 .Pn slocal
|
|
meillo@78
|
800 used to depend on
|
|
meillo@74
|
801 .I ndbm ,
|
|
meillo@74
|
802 a database library.
|
|
meillo@76
|
803 The database is used to store the `\fLMessage-ID\fP's of all
|
|
meillo@76
|
804 messages delivered.
|
|
meillo@74
|
805 This enables
|
|
meillo@74
|
806 .Pn slocal
|
|
meillo@74
|
807 to suppress delivering the same message to the same user twice.
|
|
meillo@74
|
808 (This features was enabled by the
|
|
meillo@74
|
809 .Sw -suppressdup
|
|
meillo@74
|
810 switch.)
|
|
meillo@74
|
811 .P
|
|
meillo@100
|
812 A variety of versions of the database library exist.
|
|
meillo@78
|
813 .[
|
|
meillo@78
|
814 wolter unix incompat notes dbm
|
|
meillo@78
|
815 .]
|
|
meillo@74
|
816 Complicated autoconf code was needed to detect them correctly.
|
|
meillo@74
|
817 Further more, the configure switches
|
|
meillo@74
|
818 .Sw --with-ndbm=ARG
|
|
meillo@74
|
819 and
|
|
meillo@74
|
820 .Sw --with-ndbmheader=ARG
|
|
meillo@74
|
821 were added to help with difficult setups that would
|
|
meillo@78
|
822 not be detected automatically or correctly.
|
|
meillo@74
|
823 .P
|
|
meillo@74
|
824 By removing the suppress duplicates feature of
|
|
meillo@74
|
825 .Pn slocal ,
|
|
meillo@74
|
826 the dependency on
|
|
meillo@74
|
827 .I ndbm
|
|
meillo@78
|
828 vanished and 120 lines of complex autoconf code could be saved.
|
|
meillo@74
|
829 .Ci ecd6d6a20cb7a1507e3a20d6c4cb3a1cf14c6bbf
|
|
meillo@89
|
830 The change removed functionality too, but that is minor to the
|
|
meillo@78
|
831 improvement by dropping the dependency and the complex autoconf code.
|
|
meillo@72
|
832
|
|
meillo@74
|
833 .U3 "mh-e Support
|
|
meillo@72
|
834 .P
|
|
meillo@74
|
835 The configure option
|
|
meillo@74
|
836 .Sw --disable-mhe
|
|
meillo@74
|
837 was removed when the mh-e support was reworked.
|
|
meillo@74
|
838 Mh-e is the Emacs front-end to MH.
|
|
meillo@76
|
839 It requires MH to provide minor additional functions.
|
|
meillo@76
|
840 The
|
|
meillo@76
|
841 .Sw --disable-mhe
|
|
meillo@76
|
842 configure option could switch these extensions off.
|
|
meillo@76
|
843 After removing the support for old versions of mh-e,
|
|
meillo@74
|
844 only the
|
|
meillo@74
|
845 .Sw -build
|
|
meillo@76
|
846 switches of
|
|
meillo@74
|
847 .Pn forw
|
|
meillo@74
|
848 and
|
|
meillo@74
|
849 .Pn repl
|
|
meillo@76
|
850 are left to be mh-e extensions.
|
|
meillo@76
|
851 They are now always built in because they add little code and complexity.
|
|
meillo@76
|
852 In consequence, the
|
|
meillo@74
|
853 .Sw --disable-mhe
|
|
meillo@76
|
854 configure option was removed
|
|
meillo@72
|
855 .Ci a7ce7b4a580d77b6c2c4d980812beb589aa4c643
|
|
meillo@74
|
856 Removing the option removed a second code setup that would have
|
|
meillo@74
|
857 needed to be tested.
|
|
meillo@76
|
858 This change was first done in nmh and thereafter merged into mmh.
|
|
meillo@76
|
859 .P
|
|
meillo@76
|
860 The interface changes in mmh require mh-e to be adjusted in order
|
|
meillo@76
|
861 to be able to use mmh as back-end.
|
|
meillo@76
|
862 This will require minor changes to mh-e, but removing the
|
|
meillo@76
|
863 .Sw -build
|
|
meillo@76
|
864 switches would require more rework.
|
|
meillo@72
|
865
|
|
meillo@74
|
866 .U3 "Masquerading
|
|
meillo@72
|
867 .P
|
|
meillo@74
|
868 The configure option
|
|
meillo@74
|
869 .Sw --enable-masquerade
|
|
meillo@76
|
870 could take up to three arguments:
|
|
meillo@76
|
871 `draft_from', `mmailid', and `username_extension'.
|
|
meillo@74
|
872 They activated different types of address masquerading.
|
|
meillo@74
|
873 All of them were implemented in the SMTP-speaking
|
|
meillo@74
|
874 .Pn post
|
|
meillo@76
|
875 command, which provided an MSA.
|
|
meillo@76
|
876 Address masquerading is an MTA's task and mmh does not cover
|
|
meillo@76
|
877 this field anymore.
|
|
meillo@76
|
878 Hence, true masquerading needs to be implemented in the external MTA.
|
|
meillo@74
|
879 .P
|
|
meillo@74
|
880 The
|
|
meillo@74
|
881 .I mmailid
|
|
meillo@74
|
882 masquerading type is the oldest one of the three and the only one
|
|
meillo@74
|
883 available in the original MH.
|
|
meillo@74
|
884 It provided a
|
|
meillo@74
|
885 .I username
|
|
meillo@74
|
886 to
|
|
meillo@74
|
887 .I fakeusername
|
|
meillo@76
|
888 mapping, based on the password file's GECOS field.
|
|
meillo@74
|
889 The man page
|
|
meillo@74
|
890 .Mp mh-tailor(5)
|
|
meillo@74
|
891 described the use case as being the following:
|
|
meillo@98
|
892 .QS
|
|
meillo@74
|
893 This is useful if you want the messages you send to always
|
|
meillo@74
|
894 appear to come from the name of an MTA alias rather than your
|
|
meillo@74
|
895 actual account name. For instance, many organizations set up
|
|
meillo@74
|
896 `First.Last' sendmail aliases for all users. If this is
|
|
meillo@74
|
897 the case, the GECOS field for each user should look like:
|
|
meillo@74
|
898 ``First [Middle] Last <First.Last>''
|
|
meillo@98
|
899 .QE
|
|
meillo@74
|
900 .P
|
|
meillo@74
|
901 As mmh sends outgoing mail via the local MTA only,
|
|
meillo@76
|
902 the best location to do such global rewrites is there.
|
|
meillo@74
|
903 Besides, the MTA is conceptionally the right location because it
|
|
meillo@74
|
904 does the reverse mapping for incoming mail (aliasing), too.
|
|
meillo@76
|
905 Further more, masquerading set up there is readily available for all
|
|
meillo@74
|
906 mail software on the system.
|
|
meillo@76
|
907 Hence, mmailid masquerading was removed.
|
|
meillo@74
|
908 .Ci 0836c8000ccb34b59410ef1c15b1b7feac70ce5f
|
|
meillo@74
|
909 .P
|
|
meillo@74
|
910 The
|
|
meillo@74
|
911 .I username_extension
|
|
meillo@76
|
912 masquerading type did not replace the username but would append a suffix,
|
|
meillo@76
|
913 specified by the
|
|
meillo@74
|
914 .Ev USERNAME_EXTENSION
|
|
meillo@76
|
915 environment variable, to it.
|
|
meillo@76
|
916 This provided support for the
|
|
meillo@74
|
917 .I user-extension
|
|
meillo@74
|
918 feature of qmail and the similar
|
|
meillo@74
|
919 .I "plussed user
|
|
meillo@74
|
920 processing of sendmail.
|
|
meillo@74
|
921 The decision to remove this username_extension masquerading was
|
|
meillo@74
|
922 motivated by the fact that
|
|
meillo@74
|
923 .Pn spost
|
|
meillo@76
|
924 hadn't supported it already.
|
|
meillo@76
|
925 .Ci 2abae0bfd0ad5bf898461e50aa4b466d641f23d9
|
|
meillo@76
|
926 Username extensions are possible in mmh, but less convenient to use.
|
|
meillo@76
|
927 .\" XXX format file %(getenv USERNAME_EXTENSION)
|
|
meillo@74
|
928 .P
|
|
meillo@74
|
929 The
|
|
meillo@74
|
930 .I draft_from
|
|
meillo@74
|
931 masquerading type instructed
|
|
meillo@74
|
932 .Pn post
|
|
meillo@84
|
933 to use the value of the
|
|
meillo@84
|
934 .Hd From
|
|
meillo@84
|
935 header field as SMTP envelope sender.
|
|
meillo@76
|
936 Sender addresses could be replaced completely.
|
|
meillo@74
|
937 .Ci b14ea6073f77b4359aaf3fddd0e105989db9
|
|
meillo@76
|
938 Mmh offers a kind of masquerading similar in effect, but
|
|
meillo@74
|
939 with technical differences.
|
|
meillo@76
|
940 As mmh does not transfer messages itself, the local MTA has final control
|
|
meillo@76
|
941 over the sender's address. Any masquerading mmh introduces may be reverted
|
|
meillo@76
|
942 by the MTA.
|
|
meillo@76
|
943 In times of pedantic spam checking, an MTA will take care to use
|
|
meillo@76
|
944 sensible envelope sender addresses to keep its own reputation up.
|
|
meillo@84
|
945 Nonetheless, the MUA can set the
|
|
meillo@84
|
946 .Hd From
|
|
meillo@84
|
947 header field and thereby propose
|
|
meillo@76
|
948 a sender address to the MTA.
|
|
meillo@74
|
949 The MTA may then decide to take that one or generate the canonical sender
|
|
meillo@74
|
950 address for use as envelope sender address.
|
|
meillo@74
|
951 .P
|
|
meillo@74
|
952 In mmh, the MTA will always extract the recipient and sender from the
|
|
meillo@84
|
953 message header (\c
|
|
meillo@74
|
954 .Pn sendmail 's
|
|
meillo@74
|
955 .Sw -t
|
|
meillo@74
|
956 switch).
|
|
meillo@84
|
957 The
|
|
meillo@84
|
958 .Hd From
|
|
meillo@84
|
959 header field of the draft may be set arbitrary by the user.
|
|
meillo@74
|
960 If it is missing, the canonical sender address will be generated by the MTA.
|
|
meillo@74
|
961
|
|
meillo@74
|
962 .U3 "Remaining Options
|
|
meillo@74
|
963 .P
|
|
meillo@74
|
964 Two configure options remain in mmh.
|
|
meillo@74
|
965 One is the locking method to use:
|
|
meillo@74
|
966 .Sw --with-locking=[dot|fcntl|flock|lockf] .
|
|
meillo@76
|
967 The idea of removing all methods except the portable dot locking
|
|
meillo@76
|
968 and having that one as the default is appealing, but this change
|
|
meillo@76
|
969 requires deeper technical investigation into the topic.
|
|
meillo@76
|
970 The other option,
|
|
meillo@74
|
971 .Sw --enable-debug ,
|
|
meillo@74
|
972 compiles the programs with debugging symbols and does not strip them.
|
|
meillo@74
|
973 This option is likely to stay.
|
|
meillo@72
|
974
|
|
meillo@72
|
975
|
|
meillo@58
|
976
|
|
meillo@63
|
977
|
|
meillo@100
|
978 .H2 "Command Line Switches
|
|
meillo@58
|
979 .P
|
|
meillo@93
|
980 The command line switches of MH tools follow the X Window style.
|
|
meillo@93
|
981 They are words, introduced by a single dash.
|
|
meillo@93
|
982 For example:
|
|
meillo@93
|
983 .Cl "-truncate" .
|
|
meillo@93
|
984 Every program in mmh has two generic switches:
|
|
meillo@93
|
985 .Sw -help ,
|
|
meillo@93
|
986 to print a short message on how to use the program, and
|
|
meillo@93
|
987 .Sw -Version ,
|
|
meillo@93
|
988 to tell what version of mmh the program belongs to.
|
|
meillo@93
|
989 .P
|
|
meillo@93
|
990 Switches change the behavior of programs.
|
|
meillo@93
|
991 Programs that do one thing in one way require no switches.
|
|
meillo@93
|
992 In most cases, doing something in exactly one way is too limiting.
|
|
meillo@97
|
993 If there is basically one task to accomplish, but it should be done
|
|
meillo@93
|
994 in various ways, switches are a good approach to alter the behavior
|
|
meillo@93
|
995 of a program.
|
|
meillo@93
|
996 Changing the behavior of programs provides flexibility and customization
|
|
meillo@97
|
997 to users, but at the same time it complicates the code, documentation and
|
|
meillo@93
|
998 usage of the program.
|
|
meillo@97
|
999 .\" XXX: Ref
|
|
meillo@93
|
1000 Therefore, the number of switches should be kept small.
|
|
meillo@93
|
1001 A small set of well-chosen switches does no harm.
|
|
meillo@93
|
1002 But usually, the number of switches increases over time.
|
|
meillo@93
|
1003 Already in 1985, Rose and Romine have identified this as a major
|
|
meillo@93
|
1004 problem of MH:
|
|
meillo@93
|
1005 .[ [
|
|
meillo@93
|
1006 rose romine real work
|
|
meillo@93
|
1007 .], p. 12]
|
|
meillo@98
|
1008 .QS
|
|
meillo@93
|
1009 A complaint often heard about systems which undergo substantial development
|
|
meillo@93
|
1010 by many people over a number of years, is that more and more options are
|
|
meillo@93
|
1011 introduced which add little to the functionality but greatly increase the
|
|
meillo@93
|
1012 amount of information a user needs to know in order to get useful work done.
|
|
meillo@93
|
1013 This is usually referred to as creeping featurism.
|
|
meillo@93
|
1014 .QP
|
|
meillo@93
|
1015 Unfortunately MH, having undergone six years of off-and-on development by
|
|
meillo@93
|
1016 ten or so well-meaning programmers (the present authors included),
|
|
meillo@93
|
1017 suffers mightily from this.
|
|
meillo@98
|
1018 .QE
|
|
meillo@93
|
1019 .P
|
|
meillo@97
|
1020 Being reluctant to adding new switches \(en or `options',
|
|
meillo@97
|
1021 as Rose and Romine call them \(en is one part of a counter-action,
|
|
meillo@97
|
1022 the other part is removing hardly used switches.
|
|
meillo@97
|
1023 Nmh's tools had lots of switches already implemented,
|
|
meillo@97
|
1024 hence, cleaning up by removing some of them was the more important part
|
|
meillo@97
|
1025 of the counter-action.
|
|
meillo@93
|
1026 Removing existing functionality is always difficult because it
|
|
meillo@93
|
1027 breaks programs that use these functions.
|
|
meillo@93
|
1028 Also, for every obsolete feature, there'll always be someone who still
|
|
meillo@93
|
1029 uses it and thus opposes its removal.
|
|
meillo@93
|
1030 This puts the developer into the position,
|
|
meillo@93
|
1031 where sensible improvements to style are regarded as destructive acts.
|
|
meillo@97
|
1032 Yet, living with the featurism is far worse, in my eyes, because
|
|
meillo@97
|
1033 future needs will demand adding further features,
|
|
meillo@93
|
1034 worsening the situation more and more.
|
|
meillo@93
|
1035 Rose and Romine added in a footnote,
|
|
meillo@93
|
1036 ``[...]
|
|
meillo@93
|
1037 .Pn send
|
|
meillo@93
|
1038 will no doubt acquire an endless number of switches in the years to come.''
|
|
meillo@97
|
1039 Although clearly humorous, the comment points to the nature of the problem.
|
|
meillo@97
|
1040 Refusing to add any new switches would encounter the problem at its root,
|
|
meillo@97
|
1041 but this is not practical.
|
|
meillo@97
|
1042 New needs will require new switches and it would be unwise to block
|
|
meillo@97
|
1043 them strictly.
|
|
meillo@97
|
1044 Nevertheless, removing obsolete switches still is an effective approach
|
|
meillo@97
|
1045 to deal with the problem.
|
|
meillo@97
|
1046 Working on an experimental branch without an established user base,
|
|
meillo@97
|
1047 eased my work because I did not offend users when I removed existing
|
|
meillo@110
|
1048 functions.
|
|
meillo@93
|
1049 .P
|
|
meillo@93
|
1050 Rose and Romine counted 24 visible and 9 more hidden switches for
|
|
meillo@93
|
1051 .Pn send .
|
|
meillo@97
|
1052 In nmh, they increased up to 32 visible and 12 hidden ones.
|
|
meillo@97
|
1053 At the time of writing, no more than 7 visible switches and 1 hidden switch
|
|
meillo@97
|
1054 have remained in mmh's
|
|
meillo@97
|
1055 .Pn send .
|
|
meillo@97
|
1056 (These numbers include two generic switches, help and version.)
|
|
meillo@93
|
1057 .P
|
|
meillo@97
|
1058 Fig. XXX
|
|
meillo@93
|
1059 .\" XXX Ref
|
|
meillo@97
|
1060 displays the number of switches for each of the tools that is available
|
|
meillo@97
|
1061 in both, nmh and mmh.
|
|
meillo@100
|
1062 The tools are sorted by the number of switches they had in nmh.
|
|
meillo@100
|
1063 Visible and hidden switches were counted,
|
|
meillo@97
|
1064 but not the generic help and version switches.
|
|
meillo@93
|
1065 Whereas in the beginning of the project, the average tool had 11 switches,
|
|
meillo@93
|
1066 now it has no more than 5 \(en only half as many.
|
|
meillo@93
|
1067 If the `no' switches and similar inverse variant are folded onto
|
|
meillo@100
|
1068 their counter-parts, the average tool had 8 switches in pre-mmh times and
|
|
meillo@100
|
1069 has 4 now.
|
|
meillo@93
|
1070 The total number of functional switches in mmh dropped from 465
|
|
meillo@93
|
1071 to 234.
|
|
meillo@58
|
1072
|
|
meillo@93
|
1073 .KS
|
|
meillo@93
|
1074 .in 1c
|
|
meillo@93
|
1075 .so input/switches.grap
|
|
meillo@93
|
1076 .KE
|
|
meillo@58
|
1077
|
|
meillo@93
|
1078 .P
|
|
meillo@93
|
1079 A part of the switches vanished after functions were removed.
|
|
meillo@93
|
1080 This was the case for network mail transfer, for instance.
|
|
meillo@97
|
1081 Sometimes, however, the work flow was the other way:
|
|
meillo@97
|
1082 I looked through the
|
|
meillo@97
|
1083 .Mp mh-chart (7)
|
|
meillo@97
|
1084 man page to identify the tools with apparently too many switches.
|
|
meillo@97
|
1085 Then considering the value of each of the switches by examining
|
|
meillo@97
|
1086 the tool's man page and source code, aided by recherche and testing.
|
|
meillo@97
|
1087 This way, the removal of functions was suggested by the aim to reduce
|
|
meillo@97
|
1088 the number of switches per command.
|
|
meillo@97
|
1089
|
|
meillo@58
|
1090
|
|
meillo@93
|
1091 .U3 "Draft Folder Facility
|
|
meillo@93
|
1092 .P
|
|
meillo@100
|
1093 A change early in the project was the complete transition from
|
|
meillo@93
|
1094 the single draft message to the draft folder facility.
|
|
meillo@97
|
1095 .Ci 337338b404931f06f0db2119c9e145e8ca5a9860
|
|
meillo@109
|
1096 The draft folder facility was introduced in the mid-eighties, when
|
|
meillo@100
|
1097 Rose and Romine called it a ``relatively new feature''.
|
|
meillo@93
|
1098 .[
|
|
meillo@93
|
1099 rose romine real work
|
|
meillo@93
|
1100 .]
|
|
meillo@110
|
1101 Since then, the facility had existed but was inactive by default.
|
|
meillo@93
|
1102 The default activation and the related rework of the tools made it
|
|
meillo@93
|
1103 possible to remove the
|
|
meillo@93
|
1104 .Sw -[no]draftfolder ,
|
|
meillo@93
|
1105 and
|
|
meillo@93
|
1106 .Sw -draftmessage
|
|
meillo@93
|
1107 switches from
|
|
meillo@93
|
1108 .Pn comp ,
|
|
meillo@93
|
1109 .Pn repl ,
|
|
meillo@93
|
1110 .Pn forw ,
|
|
meillo@93
|
1111 .Pn dist ,
|
|
meillo@93
|
1112 .Pn whatnow ,
|
|
meillo@93
|
1113 and
|
|
meillo@93
|
1114 .Pn send .
|
|
meillo@97
|
1115 .Ci 337338b404931f06f0db2119c9e145e8ca5a9860
|
|
meillo@97
|
1116 The only flexibility removed with this change is having multiple
|
|
meillo@97
|
1117 draft folders within one profile.
|
|
meillo@97
|
1118 I consider this a theoretical problem only.
|
|
meillo@93
|
1119 In the same go, the
|
|
meillo@93
|
1120 .Sw -draft
|
|
meillo@93
|
1121 switch of
|
|
meillo@93
|
1122 .Pn anno ,
|
|
meillo@93
|
1123 .Pn refile ,
|
|
meillo@93
|
1124 and
|
|
meillo@93
|
1125 .Pn send
|
|
meillo@93
|
1126 was removed.
|
|
meillo@93
|
1127 The special-casing of `the' draft message became irrelevant after
|
|
meillo@93
|
1128 the rework of the draft system.
|
|
meillo@93
|
1129 (See Sec. XXX.)
|
|
meillo@95
|
1130 Equally,
|
|
meillo@95
|
1131 .Pn comp
|
|
meillo@95
|
1132 lost its
|
|
meillo@95
|
1133 .Sw -file
|
|
meillo@95
|
1134 switch.
|
|
meillo@95
|
1135 The draft folder facility, together with the
|
|
meillo@95
|
1136 .Sw -form
|
|
meillo@95
|
1137 switch, are sufficient.
|
|
meillo@93
|
1138
|
|
meillo@95
|
1139
|
|
meillo@102
|
1140 .U3 "In Place Editing
|
|
meillo@93
|
1141 .P
|
|
meillo@93
|
1142 .Pn anno
|
|
meillo@93
|
1143 had the switches
|
|
meillo@93
|
1144 .Sw -[no]inplace
|
|
meillo@100
|
1145 to either annotate the message in place and thus preserve hard links,
|
|
meillo@93
|
1146 or annotate a copy to replace the original message, breaking hard links.
|
|
meillo@97
|
1147 Following the assumption that linked messages should truly be the
|
|
meillo@97
|
1148 same message, and annotating it should not break the link, the
|
|
meillo@93
|
1149 .Sw -[no]inplace
|
|
meillo@93
|
1150 switches were removed and the previous default
|
|
meillo@93
|
1151 .Sw -inplace
|
|
meillo@93
|
1152 was made the only behavior.
|
|
meillo@97
|
1153 .Ci c8195849d2e366c569271abb0f5f60f4ebf0b4d0
|
|
meillo@93
|
1154 The
|
|
meillo@93
|
1155 .Sw -[no]inplace
|
|
meillo@93
|
1156 switches of
|
|
meillo@93
|
1157 .Pn repl ,
|
|
meillo@93
|
1158 .Pn forw ,
|
|
meillo@93
|
1159 and
|
|
meillo@93
|
1160 .Pn dist
|
|
meillo@93
|
1161 could be removed, too, as they were simply passed through to
|
|
meillo@93
|
1162 .Pn anno .
|
|
meillo@93
|
1163 .P
|
|
meillo@93
|
1164 .Pn burst
|
|
meillo@93
|
1165 also had
|
|
meillo@93
|
1166 .Sw -[no]inplace
|
|
meillo@95
|
1167 switches, but with different meaning.
|
|
meillo@95
|
1168 With
|
|
meillo@95
|
1169 .Sw -inplace ,
|
|
meillo@95
|
1170 the digest had been replaced by the table of contents (i.e. the
|
|
meillo@110
|
1171 introduction text) and the burst messages were placed right
|
|
meillo@95
|
1172 after this message, renumbering all following messages.
|
|
meillo@95
|
1173 Also, any trailing text of the digest was lost, though,
|
|
meillo@95
|
1174 in practice, it usually consists of an end-of-digest marker only.
|
|
meillo@95
|
1175 Nontheless, this behavior appeared less elegant than the
|
|
meillo@95
|
1176 .Sw -noinplace
|
|
meillo@95
|
1177 behavior, which already had been the default.
|
|
meillo@95
|
1178 Nmh's
|
|
meillo@95
|
1179 .Mp burst (1)
|
|
meillo@95
|
1180 man page reads:
|
|
meillo@95
|
1181 .sp \n(PDu
|
|
meillo@98
|
1182 .QS
|
|
meillo@93
|
1183 If -noinplace is given, each digest is preserved, no table
|
|
meillo@93
|
1184 of contents is produced, and the messages contained within
|
|
meillo@93
|
1185 the digest are placed at the end of the folder. Other messages
|
|
meillo@93
|
1186 are not tampered with in any way.
|
|
meillo@98
|
1187 .QE
|
|
meillo@95
|
1188 .LP
|
|
meillo@93
|
1189 The decision to drop the
|
|
meillo@93
|
1190 .Sw -inplace
|
|
meillo@95
|
1191 behavior was supported by the code complexity and the possible data loss
|
|
meillo@95
|
1192 it caused.
|
|
meillo@93
|
1193 .Sw -noinplace
|
|
meillo@95
|
1194 was chosen to be the definitive behavior.
|
|
meillo@97
|
1195 .Ci 68a686adeb39223a5e1ad35e4a24890ec053679d
|
|
meillo@93
|
1196
|
|
meillo@95
|
1197
|
|
meillo@95
|
1198 .U3 "Forms and Format Strings
|
|
meillo@93
|
1199 .P
|
|
meillo@95
|
1200 Historically, the tools that had
|
|
meillo@95
|
1201 .Sw -form
|
|
meillo@95
|
1202 switches to supply a form file had
|
|
meillo@95
|
1203 .Sw -format
|
|
meillo@95
|
1204 switches as well to supply the contents of a form file as a string
|
|
meillo@95
|
1205 on the command line directly.
|
|
meillo@95
|
1206 In consequence, the following two lines equaled:
|
|
meillo@95
|
1207 .VS
|
|
meillo@95
|
1208 scan -form scan.mailx
|
|
meillo@95
|
1209 scan -format "`cat .../scan.mailx`"
|
|
meillo@95
|
1210 VE
|
|
meillo@95
|
1211 The
|
|
meillo@95
|
1212 .Sw -format
|
|
meillo@95
|
1213 switches were dropped in favor for extending the
|
|
meillo@95
|
1214 .Sw -form
|
|
meillo@95
|
1215 switches.
|
|
meillo@97
|
1216 .Ci f51956be123db66b00138f80464d06f030dbb88d
|
|
meillo@95
|
1217 If their argument starts with an equal sign (`='),
|
|
meillo@95
|
1218 then the rest of the argument is taken as a format string,
|
|
meillo@95
|
1219 otherwise the arguments is treated as the name of a format file.
|
|
meillo@95
|
1220 Thus, now the following two lines equal:
|
|
meillo@95
|
1221 .VS
|
|
meillo@95
|
1222 scan -form scan.mailx
|
|
meillo@95
|
1223 scan -form "=`cat .../scan.mailx`"
|
|
meillo@95
|
1224 VE
|
|
meillo@95
|
1225 This rework removed the prefix collision between
|
|
meillo@95
|
1226 .Sw -form
|
|
meillo@95
|
1227 and
|
|
meillo@95
|
1228 .Sw -format .
|
|
meillo@95
|
1229 Now, typing
|
|
meillo@95
|
1230 .Sw -fo
|
|
meillo@95
|
1231 suffices to specify form or format string.
|
|
meillo@95
|
1232 .P
|
|
meillo@95
|
1233 The different meaning of
|
|
meillo@95
|
1234 .Sw -format
|
|
meillo@95
|
1235 for
|
|
meillo@95
|
1236 .Pn repl
|
|
meillo@95
|
1237 and
|
|
meillo@95
|
1238 .Pn forw
|
|
meillo@95
|
1239 was removed in mmh.
|
|
meillo@95
|
1240 .Pn forw
|
|
meillo@95
|
1241 was completely switched to MIME-type forwarding, thus removing the
|
|
meillo@95
|
1242 .Sw -[no]format .
|
|
meillo@97
|
1243 .Ci 6e271608b7b9c23771523f88d23a4d3593010cf1
|
|
meillo@95
|
1244 For
|
|
meillo@95
|
1245 .Pn repl ,
|
|
meillo@95
|
1246 the
|
|
meillo@95
|
1247 .Sw -[no]format
|
|
meillo@95
|
1248 switches were reworked to
|
|
meillo@95
|
1249 .Sw -[no]filter
|
|
meillo@95
|
1250 switches.
|
|
meillo@97
|
1251 .Ci 67411b1f95d6ec987b4c732459e1ba8a8ac192c6
|
|
meillo@95
|
1252 The
|
|
meillo@95
|
1253 .Sw -format
|
|
meillo@95
|
1254 switches of
|
|
meillo@95
|
1255 .Pn send
|
|
meillo@95
|
1256 and
|
|
meillo@95
|
1257 .Pn post ,
|
|
meillo@95
|
1258 which had a third meaning,
|
|
meillo@95
|
1259 were removed likewise.
|
|
meillo@97
|
1260 .Ci f3cb7cde0e6f10451b6848678d95860d512224b9
|
|
meillo@95
|
1261 Eventually, the ambiguity of the
|
|
meillo@95
|
1262 .Sw -format
|
|
meillo@95
|
1263 switches was resolved by not anymore having any such switch in mmh.
|
|
meillo@95
|
1264
|
|
meillo@95
|
1265
|
|
meillo@95
|
1266 .U3 "MIME Tools
|
|
meillo@95
|
1267 .P
|
|
meillo@95
|
1268 The MIME tools, which were once part of
|
|
meillo@100
|
1269 .Pn mhn
|
|
meillo@100
|
1270 [sic!],
|
|
meillo@95
|
1271 had several switches that added little practical value to the programs.
|
|
meillo@95
|
1272 The
|
|
meillo@95
|
1273 .Sw -[no]realsize
|
|
meillo@95
|
1274 switches of
|
|
meillo@95
|
1275 .Pn mhbuild
|
|
meillo@95
|
1276 and
|
|
meillo@95
|
1277 .Pn mhlist
|
|
meillo@97
|
1278 were removed, doing real size calculations always now
|
|
meillo@97
|
1279 .Ci 8d8f1c3abc586c005c904e52c4adbfe694d2201c ,
|
|
meillo@97
|
1280 as
|
|
meillo@95
|
1281 ``This provides an accurate count at the expense of a small delay.''
|
|
meillo@95
|
1282 This small delay is not noticable on modern systems.
|
|
meillo@95
|
1283 .P
|
|
meillo@95
|
1284 The
|
|
meillo@95
|
1285 .Sw -[no]check
|
|
meillo@95
|
1286 switches were removed together with the support for
|
|
meillo@95
|
1287 .Hd Content-MD5
|
|
meillo@95
|
1288 header fields.
|
|
meillo@95
|
1289 .[
|
|
meillo@95
|
1290 rfc 1864
|
|
meillo@95
|
1291 .]
|
|
meillo@97
|
1292 .Ci 31dc797eb5178970d68962ca8939da3fd9a8efda
|
|
meillo@95
|
1293 (See Sec. XXX)
|
|
meillo@95
|
1294 .P
|
|
meillo@95
|
1295 The
|
|
meillo@95
|
1296 .Sw -[no]ebcdicsafe
|
|
meillo@95
|
1297 and
|
|
meillo@95
|
1298 .Sw -[no]rfc934mode
|
|
meillo@95
|
1299 switches of
|
|
meillo@95
|
1300 .Pn mhbuild
|
|
meillo@95
|
1301 were removed because they are considered obsolete.
|
|
meillo@97
|
1302 .Ci 01a3480928da485b4d6109d36d751dfa71799d58
|
|
meillo@97
|
1303 .Ci 3363e2624dce0eb8164cf8b3f1ab385c8ff72e88
|
|
meillo@95
|
1304 .P
|
|
meillo@95
|
1305 Content caching of external MIME parts, activated with the
|
|
meillo@95
|
1306 .Sw -rcache
|
|
meillo@95
|
1307 and
|
|
meillo@95
|
1308 .Sw -wcache
|
|
meillo@95
|
1309 switches was completely removed.
|
|
meillo@97
|
1310 .Ci d1fefd9f614e4dc3cda16da6c69133c1b2005269
|
|
meillo@97
|
1311 External MIME parts are rare today, having a caching facility
|
|
meillo@96
|
1312 for them is appears to be unnecessary.
|
|
meillo@95
|
1313 .P
|
|
meillo@95
|
1314 In pre-MIME times,
|
|
meillo@95
|
1315 .Pn mhl
|
|
meillo@95
|
1316 had covered many tasks that are part of MIME handling today.
|
|
meillo@95
|
1317 Therefore,
|
|
meillo@95
|
1318 .Pn mhl
|
|
meillo@95
|
1319 could be simplified to a large extend, reducing the number of its
|
|
meillo@95
|
1320 switches from 21 to 6.
|
|
meillo@97
|
1321 .Ci 350ad6d3542a07639213cf2a4fe524e829c1e7b6
|
|
meillo@97
|
1322 .Ci 0e46503be3c855bddaeae3843e1b659279c35d70
|
|
meillo@95
|
1323
|
|
meillo@95
|
1324
|
|
meillo@95
|
1325 .U3 "Mail Transfer Switches
|
|
meillo@95
|
1326 .P
|
|
meillo@95
|
1327 With the removal of the mail transfer facilities, a lot of switches
|
|
meillo@95
|
1328 vanished automatically.
|
|
meillo@95
|
1329 .Pn inc
|
|
meillo@95
|
1330 lost 9 switches, namely
|
|
meillo@95
|
1331 .Sw -host ,
|
|
meillo@95
|
1332 .Sw -port ,
|
|
meillo@95
|
1333 .Sw -user ,
|
|
meillo@95
|
1334 .Sw -proxy ,
|
|
meillo@95
|
1335 .Sw -snoop ,
|
|
meillo@95
|
1336 .Sw -[no]pack ,
|
|
meillo@95
|
1337 as well as
|
|
meillo@95
|
1338 .Sw -sasl
|
|
meillo@95
|
1339 and
|
|
meillo@95
|
1340 .Sw -saslmech .
|
|
meillo@95
|
1341 .Pn send
|
|
meillo@95
|
1342 and
|
|
meillo@95
|
1343 .Pn post
|
|
meillo@95
|
1344 lost 11 switches each, namely
|
|
meillo@95
|
1345 .Sw -server ,
|
|
meillo@95
|
1346 .Sw -port ,
|
|
meillo@95
|
1347 .Sw -client ,
|
|
meillo@95
|
1348 .Sw -user ,
|
|
meillo@95
|
1349 .Sw -mail ,
|
|
meillo@95
|
1350 .Sw -saml ,
|
|
meillo@95
|
1351 .Sw -send ,
|
|
meillo@95
|
1352 .Sw -soml ,
|
|
meillo@95
|
1353 .Sw -snoop ,
|
|
meillo@95
|
1354 as well as
|
|
meillo@95
|
1355 .Sw -sasl ,
|
|
meillo@95
|
1356 .Sw -saslmech ,
|
|
meillo@95
|
1357 and
|
|
meillo@95
|
1358 .Sw -tls .
|
|
meillo@95
|
1359 .Pn send
|
|
meillo@95
|
1360 had the switches only to pass them further to
|
|
meillo@95
|
1361 .Pn post ,
|
|
meillo@95
|
1362 because the user would invoke
|
|
meillo@95
|
1363 .Pn post
|
|
meillo@95
|
1364 not directly, but through
|
|
meillo@95
|
1365 .Pn send .
|
|
meillo@95
|
1366 All these switches, except
|
|
meillo@95
|
1367 .Sw -snoop
|
|
meillo@95
|
1368 were usually defined as default switches in the user's profile,
|
|
meillo@95
|
1369 but hardly given in interactive usage.
|
|
meillo@95
|
1370 .P
|
|
meillo@95
|
1371 Of course, those switches did not really ``vanish'', but the configuration
|
|
meillo@95
|
1372 they did was handed over to external MSAs and MRAs.
|
|
meillo@95
|
1373 Instead of setting up the mail transfer in mmh, it is set up in
|
|
meillo@95
|
1374 external tools.
|
|
meillo@95
|
1375 Yet, this simplifies mmh.
|
|
meillo@95
|
1376 Specialized external tools will likely have simple configuration files.
|
|
meillo@95
|
1377 Hence, instead of having one complicated central configuration file,
|
|
meillo@95
|
1378 the configuration of each domain is separate.
|
|
meillo@95
|
1379 Although the user needs to learn to configure each of the tools,
|
|
meillo@95
|
1380 each configuration is likely much simpler.
|
|
meillo@95
|
1381
|
|
meillo@95
|
1382
|
|
meillo@95
|
1383 .U3 "Maildrop Formats
|
|
meillo@95
|
1384 .P
|
|
meillo@95
|
1385 With the removal of MMDF maildrop format support,
|
|
meillo@95
|
1386 .Pn packf
|
|
meillo@95
|
1387 and
|
|
meillo@95
|
1388 .Pn rcvpack
|
|
meillo@95
|
1389 no longer needed their
|
|
meillo@95
|
1390 .Sw -mbox
|
|
meillo@95
|
1391 and
|
|
meillo@95
|
1392 .Sw -mmdf
|
|
meillo@95
|
1393 switches.
|
|
meillo@95
|
1394 .Sw -mbox
|
|
meillo@95
|
1395 is the sole behavior now.
|
|
meillo@97
|
1396 .Ci 3916ab66ad5d183705ac12357621ea8661afd3c0
|
|
meillo@95
|
1397 In the same go,
|
|
meillo@95
|
1398 .Pn packf
|
|
meillo@97
|
1399 and
|
|
meillo@97
|
1400 .Pn rcvpack
|
|
meillo@97
|
1401 were reworked (see Sec. XXX) and their
|
|
meillo@95
|
1402 .Sw -file
|
|
meillo@95
|
1403 switch became unnecessary.
|
|
meillo@97
|
1404 .Ci ca1023716d4c2ab890696f3e41fa0d94267a940e
|
|
meillo@95
|
1405
|
|
meillo@95
|
1406
|
|
meillo@95
|
1407 .U3 "Terminal Magic
|
|
meillo@95
|
1408 .P
|
|
meillo@95
|
1409 Mmh's tools will no longer clear the screen (\c
|
|
meillo@95
|
1410 .Pn scan 's
|
|
meillo@95
|
1411 and
|
|
meillo@95
|
1412 .Pn mhl 's
|
|
meillo@95
|
1413 .Sw -[no]clear
|
|
meillo@97
|
1414 switches
|
|
meillo@97
|
1415 .Ci e57b17343dcb3ff373ef4dd089fbe778f0c7c270
|
|
meillo@97
|
1416 .Ci 943765e7ac5693ae177fd8d2b5a2440e53ce816e ).
|
|
meillo@95
|
1417 Neither will
|
|
meillo@95
|
1418 .Pn mhl
|
|
meillo@95
|
1419 ring the bell (\c
|
|
meillo@97
|
1420 .Sw -[no]bell
|
|
meillo@97
|
1421 .Ci e11983f44e59d8de236affa5b0d0d3067c192e24 )
|
|
meillo@95
|
1422 nor page the output itself (\c
|
|
meillo@97
|
1423 .Sw -length
|
|
meillo@97
|
1424 .Ci 5b9d883db0318ed2b84bb82dee880d7381f99188 ).
|
|
meillo@95
|
1425 .P
|
|
meillo@95
|
1426 Generally, the pager to use is no longer specified with the
|
|
meillo@95
|
1427 .Sw -[no]moreproc
|
|
meillo@95
|
1428 command line switches for
|
|
meillo@95
|
1429 .Pn mhl
|
|
meillo@95
|
1430 and
|
|
meillo@95
|
1431 .Pn show /\c
|
|
meillo@95
|
1432 .Pn mhshow .
|
|
meillo@97
|
1433 .Ci 39e87a75b5c2d3572ec72e717720b44af291e88a
|
|
meillo@95
|
1434 .P
|
|
meillo@95
|
1435 .Pn prompter
|
|
meillo@95
|
1436 lost its
|
|
meillo@95
|
1437 .Sw -erase
|
|
meillo@95
|
1438 and
|
|
meillo@95
|
1439 .Sw -kill
|
|
meillo@95
|
1440 switches because today the terminal cares for the line editing keys.
|
|
meillo@95
|
1441
|
|
meillo@95
|
1442
|
|
meillo@95
|
1443 .U3 "Header Printing
|
|
meillo@95
|
1444 .P
|
|
meillo@95
|
1445 .Pn folder 's
|
|
meillo@95
|
1446 data output is self-explaining enough that
|
|
meillo@95
|
1447 displaying the header line makes few sense.
|
|
meillo@95
|
1448 Hence, the
|
|
meillo@95
|
1449 .Sw -[no]header
|
|
meillo@95
|
1450 switch was removed and headers are never printed.
|
|
meillo@97
|
1451 .Ci 601cc73d1fa05ce96faa728f036d6c51b91701c7
|
|
meillo@95
|
1452 .P
|
|
meillo@95
|
1453 In
|
|
meillo@95
|
1454 .Pn mhlist ,
|
|
meillo@95
|
1455 the
|
|
meillo@95
|
1456 .Sw -[no]header
|
|
meillo@95
|
1457 switches were removed, too.
|
|
meillo@97
|
1458 .Ci b24f96523aaf60e44e04a3ffb1d22e69a13a602f
|
|
meillo@95
|
1459 But in this case headers are always printed,
|
|
meillo@95
|
1460 because the output is not self-explaining.
|
|
meillo@95
|
1461 .P
|
|
meillo@95
|
1462 .Pn scan
|
|
meillo@95
|
1463 also had
|
|
meillo@95
|
1464 .Sw -[no]header
|
|
meillo@95
|
1465 switches.
|
|
meillo@95
|
1466 Printing the header had been sensible until the introduction of
|
|
meillo@95
|
1467 format strings made it impossible to display the column headings.
|
|
meillo@95
|
1468 Only the folder name and the current date remained to be printed.
|
|
meillo@95
|
1469 As this information can be perfectly retrieved by
|
|
meillo@95
|
1470 .Pn folder
|
|
meillo@95
|
1471 and
|
|
meillo@95
|
1472 .Pn date ,
|
|
meillo@95
|
1473 consequently, the switches were removed.
|
|
meillo@97
|
1474 .Ci c477dc5d1d03fa6d9a8ab3dd3508c63cbddc044e
|
|
meillo@95
|
1475 .P
|
|
meillo@95
|
1476 By removing all
|
|
meillo@95
|
1477 .Sw -header
|
|
meillo@95
|
1478 switches, the collision with
|
|
meillo@95
|
1479 .Sw -help
|
|
meillo@95
|
1480 on the first two letters was resolved.
|
|
meillo@95
|
1481 Currently,
|
|
meillo@95
|
1482 .Sw -h
|
|
meillo@95
|
1483 evaluates to
|
|
meillo@95
|
1484 .Sw -help
|
|
meillo@95
|
1485 for all tools of mmh.
|
|
meillo@95
|
1486
|
|
meillo@95
|
1487
|
|
meillo@95
|
1488 .U3 "Suppressing Edits or the WhatNow Shell
|
|
meillo@95
|
1489 .P
|
|
meillo@95
|
1490 The
|
|
meillo@95
|
1491 .Sw -noedit
|
|
meillo@100
|
1492 switch of
|
|
meillo@95
|
1493 .Pn comp ,
|
|
meillo@95
|
1494 .Pn repl ,
|
|
meillo@95
|
1495 .Pn forw ,
|
|
meillo@95
|
1496 .Pn dist ,
|
|
meillo@95
|
1497 and
|
|
meillo@95
|
1498 .Pn whatnow
|
|
meillo@95
|
1499 was removed, but it can now be replaced by specifying
|
|
meillo@95
|
1500 .Sw -editor
|
|
meillo@95
|
1501 with an empty argument.
|
|
meillo@97
|
1502 .Ci 75fca31a5b9d5c1a99c74ab14c94438d8852fba9
|
|
meillo@95
|
1503 (Specifying
|
|
meillo@95
|
1504 .Cl "-editor true
|
|
meillo@95
|
1505 is nearly the same, only differing by the previous editor being set.)
|
|
meillo@95
|
1506 .P
|
|
meillo@95
|
1507 The more important change is the removal of the
|
|
meillo@95
|
1508 .Sw -nowhatnowproc
|
|
meillo@95
|
1509 switch.
|
|
meillo@97
|
1510 .Ci ee4f43cf2ef0084ec698e4e87159a94c01940622
|
|
meillo@95
|
1511 This switch had introduced an awkward behavior, as explained in nmh's
|
|
meillo@95
|
1512 man page for
|
|
meillo@95
|
1513 .Mp comp (1):
|
|
meillo@98
|
1514 .QS
|
|
meillo@98
|
1515 The \-editor editor switch indicates the editor to use for
|
|
meillo@98
|
1516 the initial edit. Upon exiting from the editor, comp will
|
|
meillo@98
|
1517 invoke the whatnow program. See whatnow(1) for a discussion
|
|
meillo@98
|
1518 of available options. The invocation of this program can be
|
|
meillo@98
|
1519 inhibited by using the \-nowhatnowproc switch. (In truth of
|
|
meillo@98
|
1520 fact, it is the whatnow program which starts the initial
|
|
meillo@98
|
1521 edit. Hence, \-nowhatnowproc will prevent any edit from
|
|
meillo@95
|
1522 occurring.)
|
|
meillo@98
|
1523 .QE
|
|
meillo@95
|
1524 .P
|
|
meillo@95
|
1525 Effectively, the
|
|
meillo@95
|
1526 .Sw -nowhatnowproc
|
|
meillo@100
|
1527 switch creates only a draft message.
|
|
meillo@95
|
1528 As
|
|
meillo@95
|
1529 .Cl "-whatnowproc true
|
|
meillo@95
|
1530 causes the same behavior, the
|
|
meillo@95
|
1531 .Sw -nowhatnowproc
|
|
meillo@95
|
1532 switch was removed for being redundant.
|
|
meillo@100
|
1533 Likely, the
|
|
meillo@95
|
1534 .Sw -nowhatnowproc
|
|
meillo@100
|
1535 switch was intended to be used by front-ends.
|
|
meillo@95
|
1536
|
|
meillo@95
|
1537
|
|
meillo@95
|
1538 .U3 "Compatibility Switches
|
|
meillo@95
|
1539 .BU
|
|
meillo@95
|
1540 The hidden
|
|
meillo@95
|
1541 .Sw -[no]total
|
|
meillo@95
|
1542 switches of
|
|
meillo@95
|
1543 .Pn flist .
|
|
meillo@95
|
1544 They were simply the inverse of the visible
|
|
meillo@95
|
1545 .Sw -[no]fast
|
|
meillo@95
|
1546 switches:
|
|
meillo@95
|
1547 .Sw -total
|
|
meillo@95
|
1548 was
|
|
meillo@95
|
1549 .Sw -nofast
|
|
meillo@95
|
1550 and
|
|
meillo@95
|
1551 .Sw -nototal
|
|
meillo@95
|
1552 was
|
|
meillo@95
|
1553 .Sw -fast .
|
|
meillo@95
|
1554 I removed the
|
|
meillo@95
|
1555 .Sw -[no]total
|
|
meillo@95
|
1556 legacy.
|
|
meillo@97
|
1557 .Ci ea21fe2c4bd23c639bef251398fae809875732ec
|
|
meillo@95
|
1558 .BU
|
|
meillo@95
|
1559 The
|
|
meillo@95
|
1560 .Sw -subject
|
|
meillo@95
|
1561 switch of
|
|
meillo@95
|
1562 .Pn sortm
|
|
meillo@95
|
1563 existed for compatibility only.
|
|
meillo@95
|
1564 It can be fully replaced by
|
|
meillo@95
|
1565 .Cl "-textfield subject
|
|
meillo@95
|
1566 thus it was removed.
|
|
meillo@97
|
1567 .Ci 00140a3c86e9def69d98ba2ffd4d6e50ef6326ea
|
|
meillo@95
|
1568
|
|
meillo@95
|
1569
|
|
meillo@95
|
1570 .U3 "Various
|
|
meillo@95
|
1571 .BU
|
|
meillo@96
|
1572 In order to avoid prefix collisions among switch names, the
|
|
meillo@95
|
1573 .Sw -version
|
|
meillo@95
|
1574 switch was renamed to
|
|
meillo@95
|
1575 .Sw -Version
|
|
meillo@95
|
1576 (with capital `V').
|
|
meillo@97
|
1577 .Ci 32b2354dbaf4bf934936eb5b102a4a3d2fdd209a
|
|
meillo@95
|
1578 Every program has the
|
|
meillo@95
|
1579 .Sw -version
|
|
meillo@95
|
1580 switch but its first three letters collided with the
|
|
meillo@95
|
1581 .Sw -verbose
|
|
meillo@95
|
1582 switch, present in many programs.
|
|
meillo@95
|
1583 The rename solved this problem once for all.
|
|
meillo@95
|
1584 Although this rename breaks a basic interface, having the
|
|
meillo@95
|
1585 .Sw -V
|
|
meillo@95
|
1586 abbreviation to display the version information, isn't all too bad.
|
|
meillo@95
|
1587 .BU
|
|
meillo@95
|
1588 .Sw -[no]preserve
|
|
meillo@95
|
1589 of
|
|
meillo@95
|
1590 .Pn refile
|
|
meillo@95
|
1591 was removed because what use was it anyway?
|
|
meillo@98
|
1592 .QS
|
|
meillo@95
|
1593 Normally when a message is refiled, for each destination
|
|
meillo@95
|
1594 folder it is assigned the number which is one above the current
|
|
meillo@95
|
1595 highest message number in that folder. Use of the
|
|
meillo@95
|
1596 \-preserv [sic!] switch will override this message renaming, and try
|
|
meillo@95
|
1597 to preserve the number of the message. If a conflict for a
|
|
meillo@95
|
1598 particular folder occurs when using the \-preserve switch,
|
|
meillo@95
|
1599 then refile will use the next available message number which
|
|
meillo@95
|
1600 is above the message number you wish to preserve.
|
|
meillo@98
|
1601 .QE
|
|
meillo@95
|
1602 .BU
|
|
meillo@95
|
1603 The removal of the
|
|
meillo@95
|
1604 .Sw -[no]reverse
|
|
meillo@95
|
1605 switches of
|
|
meillo@95
|
1606 .Pn scan
|
|
meillo@97
|
1607 .Ci 8edc5aaf86f9f77124664f6801bc6c6cdf258173
|
|
meillo@95
|
1608 is a bug fix, supported by the comments
|
|
meillo@95
|
1609 ``\-[no]reverse under #ifdef BERK (I really HATE this)''
|
|
meillo@95
|
1610 by Rose and
|
|
meillo@95
|
1611 ``Lists messages in reverse order with the `\-reverse' switch.
|
|
meillo@95
|
1612 This should be considered a bug.'' by Romine in the documentation.
|
|
meillo@97
|
1613 The question remains why neither Rose and Romine had fixed this
|
|
meillo@109
|
1614 bug in the eighties when they wrote these comments nor has anyone
|
|
meillo@95
|
1615 thereafter.
|
|
meillo@93
|
1616
|
|
meillo@93
|
1617
|
|
meillo@93
|
1618 .ig
|
|
meillo@93
|
1619
|
|
meillo@95
|
1620 forw: [no]dashstuffing(mhl)
|
|
meillo@93
|
1621
|
|
meillo@95
|
1622 mhshow: [no]pause [no]serialonly
|
|
meillo@93
|
1623
|
|
meillo@93
|
1624 mhmail: resent queued
|
|
meillo@93
|
1625 inc: snoop, (pop)
|
|
meillo@93
|
1626
|
|
meillo@95
|
1627 mhl: [no]faceproc folder sleep
|
|
meillo@95
|
1628 [no]dashstuffing(forw) digest list volume number issue number
|
|
meillo@93
|
1629
|
|
meillo@95
|
1630 prompter: [no]doteof
|
|
meillo@93
|
1631
|
|
meillo@93
|
1632 refile: [no]preserve [no]unlink [no]rmmproc
|
|
meillo@93
|
1633
|
|
meillo@95
|
1634 send: [no]forward [no]mime [no]msgid
|
|
meillo@93
|
1635 [no]push split [no]unique (sasl) width snoop [no]dashstuffing
|
|
meillo@93
|
1636 attach attachformat
|
|
meillo@93
|
1637 whatnow: (noedit) attach
|
|
meillo@93
|
1638
|
|
meillo@93
|
1639 slocal: [no]suppressdups
|
|
meillo@93
|
1640
|
|
meillo@95
|
1641 spost: [no]filter [no]backup width [no]push idanno
|
|
meillo@93
|
1642 [no]check(whom) whom(whom)
|
|
meillo@93
|
1643
|
|
meillo@93
|
1644 whom: ???
|
|
meillo@93
|
1645
|
|
meillo@95
|
1646 ..
|
|
meillo@93
|
1647
|
|
meillo@93
|
1648
|
|
meillo@93
|
1649 .ig
|
|
meillo@93
|
1650
|
|
meillo@93
|
1651 .P
|
|
meillo@93
|
1652 In the best case, all switches are unambiguous on the first character,
|
|
meillo@93
|
1653 or on the three-letter prefix for the `no' variants.
|
|
meillo@96
|
1654 Reducing switch prefix collisions, shortens the necessary prefix length
|
|
meillo@93
|
1655 the user must type.
|
|
meillo@93
|
1656 Having less switches helps best.
|
|
meillo@93
|
1657
|
|
meillo@93
|
1658 ..
|
|
meillo@58
|
1659
|
|
meillo@95
|
1660
|
|
meillo@102
|
1661 .\" XXX: whatnow prompt commands
|
|
meillo@102
|
1662
|
|
meillo@102
|
1663
|
|
meillo@95
|
1664
|
|
meillo@95
|
1665
|
|
meillo@133
|
1666 .\" --------------------------------------------------------------
|
|
meillo@74
|
1667 .H1 "Modernizing
|
|
meillo@102
|
1668 .P
|
|
meillo@118
|
1669 In the over thirty years of MH's existence, its code base was
|
|
meillo@118
|
1670 extended more and more.
|
|
meillo@118
|
1671 New features entered the project and became alternatives to the
|
|
meillo@118
|
1672 existing behavior.
|
|
meillo@118
|
1673 Relicts from several decades have gathered in the code base,
|
|
meillo@118
|
1674 but seldom obsolete features were dropped.
|
|
meillo@118
|
1675 This section describes the removing of old code
|
|
meillo@118
|
1676 and the modernizing of the default setup.
|
|
meillo@118
|
1677 It focuses on the functional aspect only;
|
|
meillo@118
|
1678 the non-functional aspects of code style are discussed in
|
|
meillo@118
|
1679 .\" FIXME REF
|
|
meillo@118
|
1680 Sec. XXX.
|
|
meillo@58
|
1681
|
|
meillo@58
|
1682
|
|
meillo@100
|
1683 .H2 "Code Relicts
|
|
meillo@0
|
1684 .P
|
|
meillo@109
|
1685 My position to drop obsolete functions of mmh, in order to remove old code,
|
|
meillo@104
|
1686 is much more revolutional than the nmh community likes to have it.
|
|
meillo@104
|
1687 Working on an experimental version, I was able to quickly drop
|
|
meillo@104
|
1688 functionality I considered ancient.
|
|
meillo@104
|
1689 The need for consensus with peers would have slowed this process down.
|
|
meillo@104
|
1690 Without the need to justify my decisions, I was able to rush forward.
|
|
meillo@110
|
1691 In December 2011, Paul Vixie motivated the nmh developers to just
|
|
meillo@104
|
1692 do the work:
|
|
meillo@104
|
1693 .[
|
|
meillo@104
|
1694 paul vixie edginess nmh-workers
|
|
meillo@104
|
1695 .]
|
|
meillo@104
|
1696 .QS
|
|
meillo@104
|
1697 let's stop walking on egg shells with this code base. there's no need to
|
|
meillo@104
|
1698 discuss whether to keep using vfork, just note in [sic!] passing, [...]
|
|
meillo@104
|
1699 we don't need a separate branch for removing vmh
|
|
meillo@104
|
1700 or ridding ourselves of #ifdef's or removing posix replacement functions
|
|
meillo@104
|
1701 or depending on pure ansi/posix "libc".
|
|
meillo@104
|
1702 .QP
|
|
meillo@104
|
1703 these things should each be a day or two of work and the "main branch"
|
|
meillo@104
|
1704 should just be modern. [...]
|
|
meillo@104
|
1705 let's push forward, aggressively.
|
|
meillo@104
|
1706 .QE
|
|
meillo@104
|
1707 .LP
|
|
meillo@104
|
1708 I did so already in the months before.
|
|
meillo@104
|
1709 I pushed forward.
|
|
meillo@104
|
1710 I simply dropped the cruft.
|
|
meillo@104
|
1711 .P
|
|
meillo@104
|
1712 The decision to drop a feature was based on literature research and
|
|
meillo@104
|
1713 careful thinking, but whether having had contact to this particular
|
|
meillo@104
|
1714 feature within my own computer life served as a rule of thumb.
|
|
meillo@109
|
1715 Always, I explained my reasons in the commit messages
|
|
meillo@109
|
1716 in the version control system.
|
|
meillo@104
|
1717 Hence, others can comprehend my view and argue for undoing the change
|
|
meillo@104
|
1718 if I have missed an important aspect.
|
|
meillo@109
|
1719 I was quick in dropping parts.
|
|
meillo@109
|
1720 I rather re-included falsely dropped parts than going a slower pace.
|
|
meillo@109
|
1721 Mmh is experimental work; it required tough decisions.
|
|
meillo@12
|
1722
|
|
meillo@102
|
1723
|
|
meillo@104
|
1724 .U3 "Forking
|
|
meillo@12
|
1725 .P
|
|
meillo@109
|
1726 Being a tool chest, MH creates many processes.
|
|
meillo@104
|
1727 In earlier times
|
|
meillo@104
|
1728 .Fu fork()
|
|
meillo@104
|
1729 had been an expensive system call, because the process's image needed
|
|
meillo@104
|
1730 to be duplicated completely at once.
|
|
meillo@109
|
1731 This was especially painful in the common case when the image gets
|
|
meillo@104
|
1732 replaced by a call to
|
|
meillo@104
|
1733 .Fu exec()
|
|
meillo@104
|
1734 right after having forked the child process.
|
|
meillo@104
|
1735 The
|
|
meillo@104
|
1736 .Fu vfork()
|
|
meillo@104
|
1737 system call was invented to speed up this particular case.
|
|
meillo@104
|
1738 It completely omits the duplication of the image.
|
|
meillo@104
|
1739 On old systems this resulted in significant speed ups.
|
|
meillo@104
|
1740 Therefore MH used
|
|
meillo@104
|
1741 .Fu vfork()
|
|
meillo@104
|
1742 whenever possible.
|
|
meillo@12
|
1743 .P
|
|
meillo@104
|
1744 Modern memory management units support copy-on-write semantics, which make
|
|
meillo@104
|
1745 .Fu fork()
|
|
meillo@104
|
1746 almost as fast as
|
|
meillo@104
|
1747 .Fu vfork() .
|
|
meillo@104
|
1748 The man page of
|
|
meillo@104
|
1749 .Mp vfork (2)
|
|
meillo@104
|
1750 in FreeBSD 8.0 states:
|
|
meillo@104
|
1751 .QS
|
|
meillo@104
|
1752 This system call will be eliminated when proper system sharing mechanisms
|
|
meillo@104
|
1753 are implemented. Users should not depend on the memory sharing semantics
|
|
meillo@104
|
1754 of vfork() as it will, in that case, be made synonymous to fork(2).
|
|
meillo@104
|
1755 .QE
|
|
meillo@104
|
1756 .LP
|
|
meillo@104
|
1757 Vixie supports the removal with the note that ``the last
|
|
meillo@104
|
1758 system on which fork was so slow that an mh user would notice it, was
|
|
meillo@104
|
1759 Eunice. that was 1987''.
|
|
meillo@104
|
1760 .[
|
|
meillo@104
|
1761 nmh-workers vixie edginess
|
|
meillo@104
|
1762 .]
|
|
meillo@104
|
1763 I replaced all calls to
|
|
meillo@104
|
1764 .Fu vfork()
|
|
meillo@104
|
1765 with calls to
|
|
meillo@104
|
1766 .Fu fork() .
|
|
meillo@109
|
1767 .Ci 40821f5c1316e9205a08375e7075909cc9968e7d
|
|
meillo@104
|
1768 .P
|
|
meillo@104
|
1769 Related to the costs of
|
|
meillo@104
|
1770 .Fu fork()
|
|
meillo@104
|
1771 is the probability of its success.
|
|
meillo@109
|
1772 In the eighties, on heavy loaded systems, calls to
|
|
meillo@104
|
1773 .Fu fork()
|
|
meillo@104
|
1774 were prone to failure.
|
|
meillo@104
|
1775 Hence, many of the
|
|
meillo@104
|
1776 .Fu fork()
|
|
meillo@104
|
1777 calls in the code were wrapped into loops to retry the
|
|
meillo@104
|
1778 .Fu fork()
|
|
meillo@109
|
1779 several times, to increase the changes to succeed, eventually.
|
|
meillo@109
|
1780 On modern systems, a failing
|
|
meillo@104
|
1781 .Fu fork()
|
|
meillo@109
|
1782 call is unusual.
|
|
meillo@104
|
1783 Hence, in the rare case when
|
|
meillo@104
|
1784 .Fu fork()
|
|
meillo@104
|
1785 fails, mmh programs simply abort.
|
|
meillo@109
|
1786 .Ci 5fbf37ee68e018998ada61eeab73e035b26834b6
|
|
meillo@12
|
1787
|
|
meillo@12
|
1788
|
|
meillo@109
|
1789 .U3 "Header Fields
|
|
meillo@104
|
1790 .BU
|
|
meillo@84
|
1791 The
|
|
meillo@84
|
1792 .Hd Encrypted
|
|
meillo@104
|
1793 header field was introduced by RFC\|822,
|
|
meillo@109
|
1794 but already marked as legacy in RFC\|2822.
|
|
meillo@109
|
1795 Today, OpenPGP provides the basis for standardized exchange of encrypted
|
|
meillo@104
|
1796 messages [RFC\|4880, RFC\|3156].
|
|
meillo@109
|
1797 Hence, the support for
|
|
meillo@104
|
1798 .Hd Encrypted
|
|
meillo@104
|
1799 header fields is removed in mmh.
|
|
meillo@109
|
1800 .Ci 064527f7b57ab050e5af13e15ad99aeeab125857
|
|
meillo@104
|
1801 .BU
|
|
meillo@84
|
1802 Native support for
|
|
meillo@84
|
1803 .Hd Face
|
|
meillo@104
|
1804 header fields has been removed, as well.
|
|
meillo@109
|
1805 .Ci 8e5be81f784682822f5e868c1bf3c8624682bd23
|
|
meillo@104
|
1806 This feature is similar to the
|
|
meillo@84
|
1807 .Hd X-Face
|
|
meillo@84
|
1808 header field in its intent,
|
|
meillo@21
|
1809 but takes a different approach to store the image.
|
|
meillo@84
|
1810 Instead of encoding the image data directly into the header field,
|
|
meillo@109
|
1811 it contains the hostname and UDP port where the image
|
|
meillo@109
|
1812 date can be retrieved.
|
|
meillo@109
|
1813 There exists even a third Face system,
|
|
meillo@109
|
1814 which is the successor of
|
|
meillo@109
|
1815 .Hd X-Face ,
|
|
meillo@109
|
1816 although it re-uses the
|
|
meillo@104
|
1817 .Hd Face
|
|
meillo@109
|
1818 header field.
|
|
meillo@109
|
1819 It was invented in 2005 and supports colored PNG images.
|
|
meillo@104
|
1820 None of the Face systems described here is popular today.
|
|
meillo@104
|
1821 Hence, mmh has no direct support for them.
|
|
meillo@104
|
1822 .BU
|
|
meillo@104
|
1823 The
|
|
meillo@104
|
1824 .Hd Content-MD5
|
|
meillo@104
|
1825 header field was introduced by RFC\|1864.
|
|
meillo@104
|
1826 It provides detection of data corruption during the transfer.
|
|
meillo@104
|
1827 But it can not ensure verbatim end-to-end delivery of the contents
|
|
meillo@104
|
1828 [RFC\|1864].
|
|
meillo@104
|
1829 The proper approach to verify content integrity in an
|
|
meillo@104
|
1830 end-to-end relationship is the use of digital cryptography.
|
|
meillo@104
|
1831 .\" XXX (RFCs FIXME).
|
|
meillo@104
|
1832 On the other hand, transfer protocols should detect corruption during
|
|
meillo@109
|
1833 the transmission.
|
|
meillo@109
|
1834 The TCP includes a checksum field therefore.
|
|
meillo@104
|
1835 These two approaches in combinations render the
|
|
meillo@104
|
1836 .Hd Content-MD5
|
|
meillo@104
|
1837 header field superfluous.
|
|
meillo@109
|
1838 Not a single one out of 4\|200 messages from two decades
|
|
meillo@109
|
1839 in an nmh-workers mailing list archive contains a
|
|
meillo@104
|
1840 .Hd Content-MD5
|
|
meillo@104
|
1841 header field.
|
|
meillo@104
|
1842 Neither did any of the 60\|000 messages in my personal mail storage.
|
|
meillo@104
|
1843 Removing the support for this header field,
|
|
meillo@104
|
1844 removed the last place where MD5 computation was needed.
|
|
meillo@109
|
1845 .Ci 31dc797eb5178970d68962ca8939da3fd9a8efda
|
|
meillo@104
|
1846 Hence, the MD5 code could be removed as well.
|
|
meillo@104
|
1847 Over 500 lines of code vanished by this one change.
|
|
meillo@104
|
1848
|
|
meillo@104
|
1849
|
|
meillo@104
|
1850 .U3 "MMDF maildrop support
|
|
meillo@21
|
1851 .P
|
|
meillo@104
|
1852 This type of format is conceptionally similar to the mbox format,
|
|
meillo@104
|
1853 but uses a different message delimiter (`\fL^A^A^A^A\fP' instead of
|
|
meillo@104
|
1854 `\fLFrom\0\fP').
|
|
meillo@104
|
1855 Mbox is the de-facto standard maildrop format on Unix,
|
|
meillo@109
|
1856 whereas the MMDF maildrop format became forgotten.
|
|
meillo@104
|
1857 I did drop MMDF maildrop format support.
|
|
meillo@109
|
1858 Mbox is the only packed mailbox format supported in mmh.
|
|
meillo@104
|
1859 .P
|
|
meillo@109
|
1860 The simplifications within the code were moderate.
|
|
meillo@109
|
1861 Mainly, the reading and writing of MMDF mailbox files was removed.
|
|
meillo@109
|
1862 But also, switches of
|
|
meillo@109
|
1863 .Pn packf
|
|
meillo@104
|
1864 and
|
|
meillo@109
|
1865 .Pn rcvpack
|
|
meillo@109
|
1866 could be removed.
|
|
meillo@109
|
1867 .Ci 3916ab66ad5d183705ac12357621ea8661afd3c0
|
|
meillo@109
|
1868 In the message parsing function
|
|
meillo@109
|
1869 .Fn sbr/m_getfld.c ,
|
|
meillo@109
|
1870 knowledge of MMDF packed mail boxes was removed.
|
|
meillo@109
|
1871 .Ci 684ec30d81e1223a282764452f4902ed4ad1c754
|
|
meillo@109
|
1872 Further code structure simplifications may be possible there,
|
|
meillo@109
|
1873 because only one single packed mailbox format is left to be supported.
|
|
meillo@104
|
1874 I have not worked on them yet because
|
|
meillo@104
|
1875 .Fu m_getfld()
|
|
meillo@104
|
1876 is heavily optimized and thus dangerous to touch.
|
|
meillo@104
|
1877 The risk of damaging the intricate workings of the optimized code is
|
|
meillo@104
|
1878 too high.
|
|
meillo@104
|
1879 .\" XXX: move somewhere else
|
|
meillo@104
|
1880 This problem is know to the developers of nmh, too.
|
|
meillo@109
|
1881 They also avoid touching this minefield.
|
|
meillo@104
|
1882
|
|
meillo@12
|
1883
|
|
meillo@101
|
1884 .U3 "Prompter's Control Keys
|
|
meillo@20
|
1885 .P
|
|
meillo@20
|
1886 The program
|
|
meillo@20
|
1887 .Pn prompter
|
|
meillo@104
|
1888 queries the user to fill in a message form.
|
|
meillo@104
|
1889 When used by
|
|
meillo@20
|
1890 .Pn comp
|
|
meillo@104
|
1891 as
|
|
meillo@104
|
1892 .Cl "comp -editor prompter" ,
|
|
meillo@20
|
1893 the resulting behavior is similar to
|
|
meillo@20
|
1894 .Pn mailx .
|
|
meillo@51
|
1895 Apparently,
|
|
meillo@20
|
1896 .Pn prompter
|
|
meillo@104
|
1897 hadn't been touched lately.
|
|
meillo@104
|
1898 Otherwise it's hardly explainable why it
|
|
meillo@20
|
1899 still offered the switches
|
|
meillo@84
|
1900 .Sw -erase
|
|
meillo@84
|
1901 .Ar chr
|
|
meillo@20
|
1902 and
|
|
meillo@84
|
1903 .Sw -kill
|
|
meillo@84
|
1904 .Ar chr
|
|
meillo@20
|
1905 to name the characters for command line editing.
|
|
meillo@21
|
1906 The times when this had been necessary are long time gone.
|
|
meillo@20
|
1907 Today these things work out-of-the-box, and if not, are configured
|
|
meillo@20
|
1908 with the standard tool
|
|
meillo@20
|
1909 .Pn stty .
|
|
meillo@104
|
1910 The switches are removed now
|
|
meillo@104
|
1911 .Ci 0bd9750710cdbab80cfb4036dd87af20afe1552f .
|
|
meillo@20
|
1912
|
|
meillo@104
|
1913
|
|
meillo@109
|
1914 .U3 "Hardcopy Terminal Support
|
|
meillo@21
|
1915 .P
|
|
meillo@109
|
1916 More of a funny anecdote is a check for being connected to a
|
|
meillo@109
|
1917 hardcopy terminal.
|
|
meillo@109
|
1918 It remained in the code until Spring 2012, when I finally removed it
|
|
meillo@104
|
1919 .Ci b7764c4a6b71d37918a97594d866258f154017ca .
|
|
meillo@109
|
1920 I would be truly happy to see such a terminal in action today,
|
|
meillo@109
|
1921 maybe even being able to work on it.
|
|
meillo@109
|
1922 But I fear my chances are null.
|
|
meillo@21
|
1923 .P
|
|
meillo@109
|
1924 The check only prevented a pager to be placed between the printing
|
|
meillo@104
|
1925 program (\c
|
|
meillo@104
|
1926 .Pn mhl )
|
|
meillo@104
|
1927 and the terminal.
|
|
meillo@109
|
1928 In nmh, this could have been ensured statically with the
|
|
meillo@104
|
1929 .Sw -nomoreproc
|
|
meillo@109
|
1930 at the command line, too.
|
|
meillo@121
|
1931 In mmh, setting the profile entry
|
|
meillo@104
|
1932 .Pe Pager
|
|
meillo@104
|
1933 or the environment variable
|
|
meillo@104
|
1934 .Ev PAGER
|
|
meillo@104
|
1935 to
|
|
meillo@109
|
1936 .Pn cat
|
|
meillo@109
|
1937 does the job.
|
|
meillo@104
|
1938
|
|
meillo@104
|
1939
|
|
meillo@21
|
1940
|
|
meillo@12
|
1941
|
|
meillo@58
|
1942 .H2 "Attachments
|
|
meillo@22
|
1943 .P
|
|
meillo@101
|
1944 The mind model of email attachments is unrelated to MIME.
|
|
meillo@101
|
1945 Although the MIME RFCs (2045 through 2049) define the technical
|
|
meillo@109
|
1946 requirements for having attachments, they do not mention the word
|
|
meillo@101
|
1947 ``attachment''.
|
|
meillo@101
|
1948 Instead of attachments, MIME talks about ``multi-part message bodies''
|
|
meillo@101
|
1949 [RFC\|2045], a more general concept.
|
|
meillo@101
|
1950 Multi-part messages are messages
|
|
meillo@101
|
1951 ``in which one or more different
|
|
meillo@101
|
1952 sets of data are combined in a single body''
|
|
meillo@101
|
1953 [RFC\|2046].
|
|
meillo@101
|
1954 MIME keeps its descriptions generic;
|
|
meillo@101
|
1955 it does not imply specific usage models.
|
|
meillo@109
|
1956 One usage model became prevalent: attachments.
|
|
meillo@101
|
1957 The idea is having a main text document with files of arbitrary kind
|
|
meillo@101
|
1958 attached to it.
|
|
meillo@101
|
1959 In MIME terms, this is a multi-part message having a text part first
|
|
meillo@110
|
1960 and parts of arbitrary type following.
|
|
meillo@101
|
1961 .P
|
|
meillo@101
|
1962 MH's MIME support is a direct implementation of the RFCs.
|
|
meillo@101
|
1963 The perception of the topic described in the RFCs is clearly visible
|
|
meillo@101
|
1964 in MH's implementation.
|
|
meillo@109
|
1965 In result, MH had all the MIME features but no idea of attachments.
|
|
meillo@109
|
1966 But users don't need all the MIME features,
|
|
meillo@109
|
1967 they want convenient attachment handling.
|
|
meillo@109
|
1968
|
|
meillo@102
|
1969
|
|
meillo@102
|
1970 .U3 "Composing MIME Messages
|
|
meillo@102
|
1971 .P
|
|
meillo@102
|
1972 In order to improve the situation on the message composing side,
|
|
meillo@102
|
1973 Jon Steinhart had added an attachment system to nmh in 2002.
|
|
meillo@101
|
1974 .Ci 7480dbc14bc90f2d872d434205c0784704213252
|
|
meillo@102
|
1975 In the file
|
|
meillo@102
|
1976 .Fn docs/README-ATTACHMENTS ,
|
|
meillo@102
|
1977 he described his motivation to do so as such:
|
|
meillo@101
|
1978 .QS
|
|
meillo@101
|
1979 Although nmh contains the necessary functionality for MIME message handing,
|
|
meillo@101
|
1980 the interface to this functionality is pretty obtuse.
|
|
meillo@101
|
1981 There's no way that I'm ever going to convince my partner to write
|
|
meillo@101
|
1982 .Pn mhbuild
|
|
meillo@101
|
1983 composition files!
|
|
meillo@101
|
1984 .QE
|
|
meillo@102
|
1985 .LP
|
|
meillo@102
|
1986 With this change, the mind model of attachments entered nmh.
|
|
meillo@102
|
1987 In the same document:
|
|
meillo@101
|
1988 .QS
|
|
meillo@101
|
1989 These changes simplify the task of managing attachments on draft files.
|
|
meillo@101
|
1990 They allow attachments to be added, listed, and deleted.
|
|
meillo@101
|
1991 MIME messages are automatically created when drafts with attachments
|
|
meillo@101
|
1992 are sent.
|
|
meillo@101
|
1993 .QE
|
|
meillo@102
|
1994 .LP
|
|
meillo@102
|
1995 Unfortunately, the attachment system,
|
|
meillo@102
|
1996 like any new facilities in nmh,
|
|
meillo@110
|
1997 was inactive by default.
|
|
meillo@101
|
1998 .P
|
|
meillo@101
|
1999 During my work in Argentina, I tried to improve the attachment system.
|
|
meillo@102
|
2000 But, because of great opposition in the nmh community,
|
|
meillo@102
|
2001 my patch died as a proposal on the mailing list, after long discussions.
|
|
meillo@101
|
2002 .[
|
|
meillo@101
|
2003 nmh-workers attachment proposal
|
|
meillo@101
|
2004 .]
|
|
meillo@110
|
2005 In January 2012, I extended the patch and applied it to mmh.
|
|
meillo@101
|
2006 .Ci 8ff284ff9167eff8f5349481529332d59ed913b1
|
|
meillo@102
|
2007 In mmh, the attachment system is active by default.
|
|
meillo@102
|
2008 Instead of command line switches, the
|
|
meillo@102
|
2009 .Pe Attachment-Header
|
|
meillo@102
|
2010 profile entry is used to specify
|
|
meillo@102
|
2011 the name of the attachment header field.
|
|
meillo@102
|
2012 It is pre-defined to
|
|
meillo@102
|
2013 .Hd Attach .
|
|
meillo@101
|
2014 .P
|
|
meillo@101
|
2015 To add an attachment to a draft, simply add an attachment header:
|
|
meillo@101
|
2016 .VS
|
|
meillo@101
|
2017 To: bob
|
|
meillo@101
|
2018 Subject: The file you wanted
|
|
meillo@101
|
2019 Attach: /path/to/the/file-bob-wanted
|
|
meillo@101
|
2020 --------
|
|
meillo@101
|
2021 Here it is.
|
|
meillo@101
|
2022 VE
|
|
meillo@101
|
2023 The header field can be added to the draft manually in the editor,
|
|
meillo@102
|
2024 or by using the `attach' command at the WhatNow prompt, or
|
|
meillo@102
|
2025 non-interactively with
|
|
meillo@101
|
2026 .Pn anno :
|
|
meillo@101
|
2027 .VS
|
|
meillo@102
|
2028 anno -append -nodate -component Attach -text /path/to/attachment
|
|
meillo@101
|
2029 VE
|
|
meillo@102
|
2030 Drafts with attachment headers are converted to MIME automatically by
|
|
meillo@102
|
2031 .Pn send .
|
|
meillo@102
|
2032 The conversion to MIME is invisible to the user.
|
|
meillo@102
|
2033 The draft stored in the draft folder is always in source form, with
|
|
meillo@101
|
2034 attachment headers.
|
|
meillo@101
|
2035 If the MIMEification fails, for instance because the file to attach
|
|
meillo@101
|
2036 is not accessible, the original draft is not changed.
|
|
meillo@101
|
2037 .P
|
|
meillo@102
|
2038 The attachment system handles the forwarding of messages, too.
|
|
meillo@101
|
2039 If the attachment header value starts with a plus character (`+'),
|
|
meillo@101
|
2040 like in
|
|
meillo@101
|
2041 .Cl "Attach: +bob 30 42" ,
|
|
meillo@101
|
2042 The given messages in the specified folder will be attached.
|
|
meillo@101
|
2043 This allowed to simplify
|
|
meillo@101
|
2044 .Pn forw .
|
|
meillo@101
|
2045 .Ci f41f04cf4ceca7355232cf7413e59afafccc9550
|
|
meillo@101
|
2046 .P
|
|
meillo@101
|
2047 Closely related to attachments is non-ASCII text content,
|
|
meillo@101
|
2048 because it requires MIME too.
|
|
meillo@102
|
2049 In nmh, the user needed to call `mime' at the WhatNow prompt
|
|
meillo@101
|
2050 to have the draft converted to MIME.
|
|
meillo@102
|
2051 This was necessary whenever the draft contained non-ASCII characters.
|
|
meillo@101
|
2052 If the user did not call `mime', a broken message would be sent.
|
|
meillo@101
|
2053 Therefore, the
|
|
meillo@101
|
2054 .Pe automimeproc
|
|
meillo@101
|
2055 profile entry could be specified to have the `mime' command invoked
|
|
meillo@102
|
2056 automatically each time.
|
|
meillo@101
|
2057 Unfortunately, this approach conflicted with with attachment system
|
|
meillo@101
|
2058 because the draft would already be in MIME format at the time
|
|
meillo@101
|
2059 when the attachment system wanted to MIMEify it.
|
|
meillo@102
|
2060 To use nmh's attachment system, `mime' must not be called at the
|
|
meillo@102
|
2061 WhatNow prompt and
|
|
meillo@101
|
2062 .Pe automimeproc
|
|
meillo@102
|
2063 must not be set in the profile.
|
|
meillo@101
|
2064 But then the case of non-ASCII text without attachment headers was
|
|
meillo@101
|
2065 not caught.
|
|
meillo@102
|
2066 All in all, the solution was complex and irritating.
|
|
meillo@102
|
2067 My patch from December 2010 would have simplified the situation.
|
|
meillo@102
|
2068 .P
|
|
meillo@101
|
2069 Mmh's current solution is even more elaborate.
|
|
meillo@101
|
2070 Any necessary MIMEification is done automatically.
|
|
meillo@101
|
2071 There is no `mime' command at the WhatNow prompt anymore.
|
|
meillo@102
|
2072 The draft will be converted automatically to MIME when either an
|
|
meillo@102
|
2073 attachment header or non-ASCII text is present.
|
|
meillo@101
|
2074 Further more, the special meaning of the hash character (`#')
|
|
meillo@102
|
2075 at line beginnings in the draft message is removed.
|
|
meillo@102
|
2076 Users need not at all deal with the whole topic.
|
|
meillo@101
|
2077 .P
|
|
meillo@102
|
2078 Although the new approach does not anymore support arbitrary MIME
|
|
meillo@102
|
2079 compositions directly, the full power of
|
|
meillo@101
|
2080 .Pn mhbuild
|
|
meillo@101
|
2081 can still be accessed.
|
|
meillo@102
|
2082 Given no attachment headers are included, the user can create
|
|
meillo@101
|
2083 .Pn mhbuild
|
|
meillo@102
|
2084 composition drafts like in nmh.
|
|
meillo@101
|
2085 Then, at the WhatNow prompt, he needs to invoke
|
|
meillo@101
|
2086 .Cl "edit mhbuild
|
|
meillo@101
|
2087 to convert it to MIME.
|
|
meillo@110
|
2088 Because the resulting draft does neither contain non-ASCII characters
|
|
meillo@102
|
2089 nor has it attachment headers, the attachment system will not touch it.
|
|
meillo@101
|
2090 .P
|
|
meillo@121
|
2091 The approach taken in mmh is tailored towards todays most common case:
|
|
meillo@101
|
2092 a text part with possibly attachments.
|
|
meillo@102
|
2093 This case is simplified a lot for users.
|
|
meillo@102
|
2094
|
|
meillo@112
|
2095
|
|
meillo@102
|
2096 .U3 "MIME Type Guessing
|
|
meillo@102
|
2097 .P
|
|
meillo@102
|
2098 The use of
|
|
meillo@101
|
2099 .Pn mhbuild
|
|
meillo@102
|
2100 composition drafts had one notable advantage over attachment headers
|
|
meillo@102
|
2101 from the programmer's point of view: The user provides the appropriate
|
|
meillo@102
|
2102 MIME types for files to include.
|
|
meillo@102
|
2103 The attachment system needs to find out the correct MIME type itself.
|
|
meillo@102
|
2104 This is a difficult task, yet it spares the user irritating work.
|
|
meillo@102
|
2105 Determining the correct MIME type of content is partly mechanical,
|
|
meillo@102
|
2106 partly intelligent work.
|
|
meillo@102
|
2107 Forcing the user to find out the correct MIME type,
|
|
meillo@102
|
2108 forces him to do partly mechanical work.
|
|
meillo@102
|
2109 Letting the computer do the work, can lead to bad choices for difficult
|
|
meillo@102
|
2110 content.
|
|
meillo@102
|
2111 For mmh, the latter option was chosen.
|
|
meillo@102
|
2112 .P
|
|
meillo@102
|
2113 Determining the MIME type by the suffix of the file name is a dumb
|
|
meillo@102
|
2114 approach, yet it is simple to implement and provides good results
|
|
meillo@102
|
2115 for the common cases.
|
|
meillo@102
|
2116 Mmh implements this approach in the
|
|
meillo@102
|
2117 .Pn print-mimetype
|
|
meillo@102
|
2118 script.
|
|
meillo@112
|
2119 .Ci 4b5944268ea0da7bb30598a27857304758ea9b44
|
|
meillo@102
|
2120 Using it is the default choice.
|
|
meillo@102
|
2121 .P
|
|
meillo@112
|
2122 A far better, though less portable, approach is the use of
|
|
meillo@102
|
2123 .Pn file .
|
|
meillo@102
|
2124 This standard tool tries to determine the type of files.
|
|
meillo@102
|
2125 Unfortunately, its capabilities and accuracy varies from system to system.
|
|
meillo@102
|
2126 Additionally, its output was only intended for human beings,
|
|
meillo@102
|
2127 but not to be used by programs.
|
|
meillo@102
|
2128 It varies much.
|
|
meillo@102
|
2129 Nevertheless, modern versions of GNU
|
|
meillo@102
|
2130 .Pn file ,
|
|
meillo@102
|
2131 which is prevalent on the popular GNU/Linux systems,
|
|
meillo@102
|
2132 provides MIME type output in machine-readable form.
|
|
meillo@102
|
2133 Although this solution is highly system-dependent,
|
|
meillo@102
|
2134 it solves the difficult problem well.
|
|
meillo@102
|
2135 On systems where GNU
|
|
meillo@102
|
2136 .Pn file ,
|
|
meillo@102
|
2137 version 5.04 or higher, is available it should be used.
|
|
meillo@102
|
2138 One needs to specify the following profile entry to do so:
|
|
meillo@112
|
2139 .Ci 3baec236a39c5c89a9bda8dbd988d643a21decc6
|
|
meillo@102
|
2140 .VS
|
|
meillo@102
|
2141 Mime-Type-Query: file -b --mime
|
|
meillo@102
|
2142 VE
|
|
meillo@102
|
2143 .LP
|
|
meillo@102
|
2144 Other versions of
|
|
meillo@102
|
2145 .Pn file
|
|
meillo@102
|
2146 might possibly be usable with wrapper scripts to reformat the output.
|
|
meillo@102
|
2147 The diversity among
|
|
meillo@102
|
2148 .Pn file
|
|
meillo@102
|
2149 implementations is great; one needs to check the local variant.
|
|
meillo@102
|
2150 .P
|
|
meillo@102
|
2151 If no MIME type can be determined, text content gets sent as
|
|
meillo@102
|
2152 `text/plain' and anything else under the generic fall-back type
|
|
meillo@102
|
2153 `application/octet-stream'.
|
|
meillo@102
|
2154 It is not possible in mmh to override the automatic MIME type guessing
|
|
meillo@102
|
2155 for a specific file.
|
|
meillo@102
|
2156 To do so, the user would need to know in advance for which file
|
|
meillo@102
|
2157 the automatic guessing does fail, or the system would require interaction.
|
|
meillo@102
|
2158 I consider both cases impractical.
|
|
meillo@102
|
2159 The existing solution should be sufficient.
|
|
meillo@102
|
2160 If not, the user may always fall back to
|
|
meillo@102
|
2161 .Pn mhbuild
|
|
meillo@102
|
2162 composition drafts and ignore the attachment system.
|
|
meillo@101
|
2163
|
|
meillo@102
|
2164
|
|
meillo@102
|
2165 .U3 "Storing Attachments
|
|
meillo@102
|
2166 .P
|
|
meillo@108
|
2167 Extracting MIME parts of a message and storing them to disk is done by
|
|
meillo@108
|
2168 .Pn mhstore .
|
|
meillo@108
|
2169 The program has two operation modes,
|
|
meillo@108
|
2170 .Sw -auto
|
|
meillo@108
|
2171 and
|
|
meillo@108
|
2172 .Sw -noauto .
|
|
meillo@108
|
2173 With the former one, each part is stored under the filename given in the
|
|
meillo@108
|
2174 MIME part's meta information, if available.
|
|
meillo@108
|
2175 This naming information is usually available for modern attachments.
|
|
meillo@108
|
2176 If no filename is available, this MIME part is stored as if
|
|
meillo@108
|
2177 .Sw -noauto
|
|
meillo@108
|
2178 would have been specified.
|
|
meillo@108
|
2179 In the
|
|
meillo@108
|
2180 .Sw -noauto
|
|
meillo@108
|
2181 mode, the parts are processed according to rules, defined by
|
|
meillo@108
|
2182 .Pe mhstore-store-*
|
|
meillo@108
|
2183 profile entries.
|
|
meillo@108
|
2184 These rules define generic filename templates for storing
|
|
meillo@108
|
2185 or commands to post-process the contents in arbitrary ways.
|
|
meillo@108
|
2186 If no matching rule is available the part is stored under a generic
|
|
meillo@108
|
2187 filename, built from message number, MIME part number, and MIME type.
|
|
meillo@108
|
2188 .P
|
|
meillo@108
|
2189 The
|
|
meillo@108
|
2190 .Sw -noauto
|
|
meillo@108
|
2191 mode had been the default in nmh because it was considered safe,
|
|
meillo@108
|
2192 in contrast to the
|
|
meillo@108
|
2193 .Sw -auto
|
|
meillo@108
|
2194 mode.
|
|
meillo@108
|
2195 In mmh,
|
|
meillo@108
|
2196 .Sw -auto
|
|
meillo@108
|
2197 is not dangerous anymore.
|
|
meillo@108
|
2198 Two changes were necessary:
|
|
meillo@108
|
2199 .BU
|
|
meillo@108
|
2200 Any directory path is removed from the proposed filename.
|
|
meillo@108
|
2201 Thus, the files are always stored in the expected directory.
|
|
meillo@108
|
2202 .Ci 41b6eadbcecf63c9a66aa5e582011987494abefb
|
|
meillo@108
|
2203 .BU
|
|
meillo@108
|
2204 Tar files are not extracted automatically any more.
|
|
meillo@108
|
2205 Thus, the rest of the file system will not be touched.
|
|
meillo@108
|
2206 .Ci 94c80042eae3383c812d9552089953f9846b1bb6
|
|
meillo@108
|
2207 .LP
|
|
meillo@108
|
2208 Now, the outcome of mmh's
|
|
meillo@108
|
2209 .Cl "mhstore -auto
|
|
meillo@110
|
2210 can be foreseen from the output of
|
|
meillo@108
|
2211 .Cl "mhlist -verbose" .
|
|
meillo@108
|
2212 .P
|
|
meillo@108
|
2213 The
|
|
meillo@108
|
2214 .Sw -noauto
|
|
meillo@108
|
2215 mode is seen to be more powerful but less convenient.
|
|
meillo@108
|
2216 On the other hand,
|
|
meillo@108
|
2217 .Sw -auto
|
|
meillo@108
|
2218 is safe now and
|
|
meillo@108
|
2219 storing attachments under their original name is intuitive.
|
|
meillo@108
|
2220 Hence,
|
|
meillo@108
|
2221 .Sw -auto
|
|
meillo@108
|
2222 serves better as the default option.
|
|
meillo@108
|
2223 .Ci 3410b680416c49a7617491af38bc1929855a331d
|
|
meillo@108
|
2224 .P
|
|
meillo@108
|
2225 Files are stored into the directory given by the
|
|
meillo@108
|
2226 .Pe Nmh-Storage
|
|
meillo@108
|
2227 profile entry, if set, or
|
|
meillo@108
|
2228 into the current working directory, otherwise.
|
|
meillo@108
|
2229 Storing to different directories is only possible with
|
|
meillo@108
|
2230 .Pe mhstore-store-*
|
|
meillo@108
|
2231 profile entries.
|
|
meillo@108
|
2232 .P
|
|
meillo@108
|
2233 Still, in both modes, existing files get overwritten silently.
|
|
meillo@108
|
2234 This can be considered a bug.
|
|
meillo@108
|
2235 Yet, each other behavior has its draw-backs, too.
|
|
meillo@108
|
2236 Refusing to replace files requires adding a
|
|
meillo@108
|
2237 .Sw -force
|
|
meillo@108
|
2238 option.
|
|
meillo@108
|
2239 Users will likely need to invoke
|
|
meillo@108
|
2240 .Pn mhstore
|
|
meillo@108
|
2241 a second time with
|
|
meillo@108
|
2242 .Sw -force
|
|
meillo@108
|
2243 then.
|
|
meillo@108
|
2244 Eventually, only the user can decide in the concrete case.
|
|
meillo@108
|
2245 This requires interaction, which I like to avoid if possible.
|
|
meillo@108
|
2246 Appending a unique suffix to the filename is another bad option.
|
|
meillo@108
|
2247 For now, the behavior remains as it is.
|
|
meillo@108
|
2248 .P
|
|
meillo@108
|
2249 In mmh, only MIME parts of type message are special in
|
|
meillo@108
|
2250 .Pn mhstore 's
|
|
meillo@108
|
2251 .Sw -auto
|
|
meillo@108
|
2252 mode.
|
|
meillo@108
|
2253 Instead of storing message/rfc822 parts as files to disk,
|
|
meillo@108
|
2254 they are stored as messages into the current mail folder.
|
|
meillo@108
|
2255 The same applies to message/partial, only, the parts are reassembled
|
|
meillo@108
|
2256 automatically before.
|
|
meillo@108
|
2257 Parts of type message/external-body are not automatically retrieved
|
|
meillo@108
|
2258 anymore. Instead, Information on how to retrieve them is output.
|
|
meillo@108
|
2259 Not supporting this rare case saved nearly one thousand lines of code.
|
|
meillo@108
|
2260 .Ci 55e1d8c654ee0f7c45b9361ce34617983b454c32
|
|
meillo@108
|
2261 .\" XXX mention somewhere else too: (The profile entry `nmh-access-ftp'
|
|
meillo@108
|
2262 .\" and sbr/ruserpass.c for reading ~/.netrc are gone now.)
|
|
meillo@108
|
2263 Not special anymore is `application/octet-stream; type=tar'.
|
|
meillo@108
|
2264 Automatically extracting such MIME parts had been the dangerous part
|
|
meillo@108
|
2265 of the
|
|
meillo@108
|
2266 .Sw -auto
|
|
meillo@108
|
2267 mode.
|
|
meillo@108
|
2268 .Ci 94c80042eae3383c812d9552089953f9846b1bb6
|
|
meillo@108
|
2269
|
|
meillo@102
|
2270
|
|
meillo@102
|
2271
|
|
meillo@102
|
2272 .U3 "Showing MIME Messages
|
|
meillo@102
|
2273 .P
|
|
meillo@114
|
2274 The program
|
|
meillo@114
|
2275 .Pn mhshow
|
|
meillo@114
|
2276 had been written to display MIME messages.
|
|
meillo@114
|
2277 It implemented the conceptional view of the MIME RFCs.
|
|
meillo@114
|
2278 Nmh's
|
|
meillo@114
|
2279 .Pn mhshow
|
|
meillo@114
|
2280 handled each MIME part independently, presenting them separately
|
|
meillo@114
|
2281 to the user.
|
|
meillo@114
|
2282 This does not match today's understanding of email attachments,
|
|
meillo@114
|
2283 where displaying a message is seen to be a single, integrated operation.
|
|
meillo@114
|
2284 Today, email messages are expected to consist of a main text part
|
|
meillo@114
|
2285 plus possibly attachments.
|
|
meillo@114
|
2286 They are not any more seen to be arbitrary MIME hierarchies with
|
|
meillo@114
|
2287 information on how to display the individual parts.
|
|
meillo@114
|
2288 I adjusted
|
|
meillo@114
|
2289 .Pn mhshow 's
|
|
meillo@114
|
2290 behavior to the modern view on the topic.
|
|
meillo@114
|
2291 .P
|
|
meillo@114
|
2292 Note that this section completely ignores the original
|
|
meillo@114
|
2293 .Pn show
|
|
meillo@114
|
2294 program, because it was not capable to display MIME messages
|
|
meillo@114
|
2295 and is no longer part of mmh.
|
|
meillo@114
|
2296 Although
|
|
meillo@114
|
2297 .Pn mhshow
|
|
meillo@114
|
2298 was renamed to
|
|
meillo@114
|
2299 .Pn show
|
|
meillo@114
|
2300 in mmh, this section uses the name
|
|
meillo@114
|
2301 .Pn mhshow ,
|
|
meillo@114
|
2302 in order to avoid confusion.
|
|
meillo@114
|
2303 .P
|
|
meillo@114
|
2304 In mmh, the basic idea is that
|
|
meillo@114
|
2305 .Pn mhshow
|
|
meillo@114
|
2306 should display a message in one single pager session.
|
|
meillo@114
|
2307 Therefore,
|
|
meillo@114
|
2308 .Pn mhshow
|
|
meillo@114
|
2309 invokes a pager session for all its output,
|
|
meillo@114
|
2310 whenever it prints to a terminal.
|
|
meillo@114
|
2311 .Ci a4197ea6ffc5c1550e8b52d5a654bcaaaee04a4e
|
|
meillo@114
|
2312 In consequence,
|
|
meillo@114
|
2313 .Pn mhl
|
|
meillo@114
|
2314 does no more invoke a pager.
|
|
meillo@114
|
2315 .Ci 0e46503be3c855bddaeae3843e1b659279c35d70
|
|
meillo@114
|
2316 With
|
|
meillo@114
|
2317 .Pn mhshow
|
|
meillo@114
|
2318 replacing the original
|
|
meillo@114
|
2319 .Pn show ,
|
|
meillo@114
|
2320 output from
|
|
meillo@114
|
2321 .Pn mhl
|
|
meillo@114
|
2322 does not go to the terminal directly, but through
|
|
meillo@114
|
2323 .Pn mhshow .
|
|
meillo@114
|
2324 Hence,
|
|
meillo@114
|
2325 .Pn mhl
|
|
meillo@114
|
2326 does not need to invoke a pager.
|
|
meillo@114
|
2327 The one and only job of
|
|
meillo@114
|
2328 .Pn mhl
|
|
meillo@114
|
2329 is to format messages or parts of them.
|
|
meillo@114
|
2330 The only place in mmh, where a pager is invoked is
|
|
meillo@114
|
2331 .Pn mhshow .
|
|
meillo@114
|
2332 .P
|
|
meillo@114
|
2333 .Pe mhshow-show-*
|
|
meillo@114
|
2334 profile entries can be used to display MIME parts in a specific way.
|
|
meillo@114
|
2335 For instance, PDF and Postscript files could be converted to plain text
|
|
meillo@114
|
2336 to display them in the terminal.
|
|
meillo@114
|
2337 In mmh, the displaying of MIME parts will always be done serially.
|
|
meillo@114
|
2338 The request to display the MIME type `multipart/parallel' in parallel
|
|
meillo@114
|
2339 is ignored.
|
|
meillo@114
|
2340 It is simply treated as `multipart/mixed'.
|
|
meillo@114
|
2341 .Ci d0581ba306a7299113a346f9b4c46ce97bc4cef6
|
|
meillo@114
|
2342 This could already be requested with the, now removed,
|
|
meillo@114
|
2343 .Sw -serialonly
|
|
meillo@114
|
2344 switch of
|
|
meillo@114
|
2345 .Pn mhshow .
|
|
meillo@114
|
2346 As MIME parts are always processed exclusively , i.e. serially,
|
|
meillo@114
|
2347 the `%e' escape in
|
|
meillo@114
|
2348 .Pe mhshow-show-*
|
|
meillo@114
|
2349 profile entries became useless and was thus removed.
|
|
meillo@114
|
2350 .Ci a20d405db09b7ccca74d3e8c57550883da49e1ae
|
|
meillo@114
|
2351 .P
|
|
meillo@114
|
2352 In the intended setup, only text content would be displayed.
|
|
meillo@114
|
2353 Non-text content would be converted to text by appropriate
|
|
meillo@114
|
2354 .Pe mhshow-show-*
|
|
meillo@114
|
2355 profile entries before, if possible and wanted.
|
|
meillo@114
|
2356 All output would be displayed in a single pager session.
|
|
meillo@114
|
2357 Other kinds of attachments are ignored.
|
|
meillo@114
|
2358 With
|
|
meillo@114
|
2359 .Pe mhshow-show-*
|
|
meillo@114
|
2360 profile entries for them, they can be displayed serially along
|
|
meillo@114
|
2361 the message.
|
|
meillo@114
|
2362 For parallel display, the attachments need to be stored to disk first.
|
|
meillo@114
|
2363 .P
|
|
meillo@114
|
2364 To display text content in foreign charsets, they need to be converted
|
|
meillo@114
|
2365 to the native charset.
|
|
meillo@114
|
2366 Therefore,
|
|
meillo@114
|
2367 .Pe mhshow-charset-*
|
|
meillo@114
|
2368 profile entries used to be needed.
|
|
meillo@121
|
2369 In mmh, the conversion is done automatically by piping the text through
|
|
meillo@114
|
2370 the
|
|
meillo@114
|
2371 .Pn iconv
|
|
meillo@114
|
2372 command, if necessary.
|
|
meillo@114
|
2373 .Ci 2433122c20baccb10b70b49c04c6b0497b5b3b60
|
|
meillo@114
|
2374 Custom
|
|
meillo@114
|
2375 .Pe mhshow-show-*
|
|
meillo@114
|
2376 rules for textual content might need a
|
|
meillo@114
|
2377 .Cl "iconv -f %c %f |
|
|
meillo@114
|
2378 prefix to have the text converted to the native charset.
|
|
meillo@114
|
2379 .P
|
|
meillo@121
|
2380 Although the conversion of foreign charsets to the native one
|
|
meillo@114
|
2381 has improved, it is not consistent enough.
|
|
meillo@114
|
2382 Further work needs to be done and
|
|
meillo@114
|
2383 the basic concepts in this field need to be re-thought.
|
|
meillo@114
|
2384 Though, the default setup of mmh displays message in foreign charsets
|
|
meillo@114
|
2385 correctly without the need to configure anything.
|
|
meillo@114
|
2386
|
|
meillo@114
|
2387
|
|
meillo@114
|
2388 .ig
|
|
meillo@114
|
2389
|
|
meillo@114
|
2390 .P
|
|
meillo@114
|
2391 mhshow/mhstore: Removed support for retrieving message/external-body parts.
|
|
meillo@114
|
2392 These tools won't download the contents automatically anymore. Instead,
|
|
meillo@114
|
2393 they print the information needed to get the contents. If someone should
|
|
meillo@114
|
2394 really receive one of those rare message/external-body messages, he can
|
|
meillo@114
|
2395 do the job manually. We save nearly a thousand lines of code. That's worth
|
|
meillo@114
|
2396 it!
|
|
meillo@114
|
2397 (The profile entry `nmh-access-ftp' and sbr/ruserpass.c for reading
|
|
meillo@114
|
2398 ~/.netrc are gone now.)
|
|
meillo@114
|
2399 .Ci 55e1d8c654ee0f7c45b9361ce34617983b454c32
|
|
meillo@114
|
2400
|
|
meillo@114
|
2401 ..
|
|
meillo@102
|
2402
|
|
meillo@58
|
2403
|
|
meillo@58
|
2404
|
|
meillo@58
|
2405 .H2 "Digital Cryptography
|
|
meillo@22
|
2406 .P
|
|
meillo@58
|
2407 Signing and encryption.
|
|
meillo@112
|
2408 .P
|
|
meillo@112
|
2409 FIXME
|
|
meillo@58
|
2410
|
|
meillo@58
|
2411
|
|
meillo@102
|
2412
|
|
meillo@133
|
2413 .H2 "Draft and Trash Folder
|
|
meillo@131
|
2414 .P
|
|
meillo@58
|
2415
|
|
meillo@131
|
2416 .U3 "Draft Folder
|
|
meillo@131
|
2417 .P
|
|
meillo@131
|
2418 In the beginning, MH had the concept of a draft message.
|
|
meillo@131
|
2419 This is the file
|
|
meillo@131
|
2420 .Fn draft
|
|
meillo@131
|
2421 in the MH directory, which is treated special.
|
|
meillo@131
|
2422 On composing a message, this draft file was used.
|
|
meillo@131
|
2423 As the draft file was one particular file, only one draft could be
|
|
meillo@131
|
2424 managed at any time.
|
|
meillo@131
|
2425 When starting to compose another message before the former one was sent,
|
|
meillo@131
|
2426 the user had to decide among:
|
|
meillo@131
|
2427 .BU
|
|
meillo@131
|
2428 Use the old draft to finish and send it before starting with a new one.
|
|
meillo@131
|
2429 .BU
|
|
meillo@131
|
2430 Discard the old draft, replacing it with the new one.
|
|
meillo@131
|
2431 .BU
|
|
meillo@131
|
2432 Preserve the old draft by refiling it to a folder.
|
|
meillo@131
|
2433 .P
|
|
meillo@131
|
2434 This was, it was only possible to work in alternation on multiple drafts.
|
|
meillo@131
|
2435 Therefore, the current draft needed to be refiled to a folder and
|
|
meillo@131
|
2436 another one re-using for editing.
|
|
meillo@131
|
2437 Working on multiple drafts at the same time was impossible.
|
|
meillo@131
|
2438 The usual approach of switching to a different MH context did not
|
|
meillo@131
|
2439 change anything.
|
|
meillo@131
|
2440 .P
|
|
meillo@131
|
2441 The draft folder facility exists to
|
|
meillo@131
|
2442 allow true parallel editing of drafts, in a straight forward way.
|
|
meillo@131
|
2443 It was introduced by Marshall T. Rose, already in 1984.
|
|
meillo@131
|
2444 Similar to other new features, the draft folder was inactive by default.
|
|
meillo@131
|
2445 Even in nmh, the highly useful draft folder was not available
|
|
meillo@131
|
2446 out-of-the-box.
|
|
meillo@131
|
2447 At least, Richard Coleman added the man page
|
|
meillo@131
|
2448 .Mp mh-draft (5)
|
|
meillo@131
|
2449 to better document the feature.
|
|
meillo@131
|
2450 .P
|
|
meillo@131
|
2451 Not using the draft folder facility has the single advantage of having
|
|
meillo@131
|
2452 the draft file at a static location.
|
|
meillo@131
|
2453 This is simple in simple cases but the concept does not scale for more
|
|
meillo@131
|
2454 complex cases.
|
|
meillo@131
|
2455 The concept of the draft message is too limited for the problem.
|
|
meillo@131
|
2456 Therefore the draft folder was introduced.
|
|
meillo@131
|
2457 It is the more powerful and more natural concept.
|
|
meillo@131
|
2458 The draft folder is a folder like any other folder in MH.
|
|
meillo@131
|
2459 Its messages can be listed like any other messages.
|
|
meillo@131
|
2460 A draft message is no longer a special case.
|
|
meillo@131
|
2461 Tools do not need special switches to work on the draft message.
|
|
meillo@131
|
2462 Hence corner-cases were removed.
|
|
meillo@131
|
2463 .P
|
|
meillo@131
|
2464 The trivial part of the work was activating the draft folder with a
|
|
meillo@131
|
2465 default name.
|
|
meillo@131
|
2466 I chose the name
|
|
meillo@131
|
2467 .Fn +drafts
|
|
meillo@131
|
2468 for obvious reasons.
|
|
meillo@131
|
2469 In consequence, the command line switches
|
|
meillo@131
|
2470 .Sw -draftfolder
|
|
meillo@131
|
2471 and
|
|
meillo@131
|
2472 .Sw -draftmessage
|
|
meillo@131
|
2473 could be removed.
|
|
meillo@131
|
2474 More difficult but also more improving was updating the tools to the
|
|
meillo@131
|
2475 new concept.
|
|
meillo@131
|
2476 For nearly three decades, the tools needed to support two draft handling
|
|
meillo@131
|
2477 approaches.
|
|
meillo@131
|
2478 By fully switching to the draft folder, the tools could be simplified
|
|
meillo@131
|
2479 by dropping the awkward draft message handling code.
|
|
meillo@131
|
2480 .Sw -draft
|
|
meillo@131
|
2481 switches were removed because operating on a draft message is no longer
|
|
meillo@131
|
2482 special.
|
|
meillo@131
|
2483 It became indistinguishable to operating on any other message.
|
|
meillo@131
|
2484 There is no more need to query the user for draft handling.
|
|
meillo@131
|
2485 It is always possible to add another new draft.
|
|
meillo@131
|
2486 Refiling drafts is without difference to refiling other messages.
|
|
meillo@131
|
2487 All these special cases are gone.
|
|
meillo@131
|
2488 Yet, one draft-related switch remained.
|
|
meillo@131
|
2489 .Pn comp
|
|
meillo@131
|
2490 still has
|
|
meillo@131
|
2491 .Sw -[no]use
|
|
meillo@131
|
2492 for switching between two modes:
|
|
meillo@131
|
2493 .BU
|
|
meillo@131
|
2494 .Sw -use :
|
|
meillo@131
|
2495 Modify an existing draft.
|
|
meillo@131
|
2496 .BU
|
|
meillo@131
|
2497 .Sw -nouse :
|
|
meillo@131
|
2498 Compose a new draft, possibly taking some existing message as a form.
|
|
meillo@131
|
2499 .P
|
|
meillo@131
|
2500 In either case, the behavior of
|
|
meillo@131
|
2501 .Pn comp
|
|
meillo@131
|
2502 is deterministic.
|
|
meillo@131
|
2503 .P
|
|
meillo@131
|
2504 .Pn send
|
|
meillo@131
|
2505 now operates on the current message in the draft folder by default.
|
|
meillo@131
|
2506 As message and folder can both be overridden by specifying them on
|
|
meillo@131
|
2507 the command line, it is possible to send any message in the mail storage
|
|
meillo@131
|
2508 by simply specifying its number and folder.
|
|
meillo@131
|
2509 In contrast to the other tools,
|
|
meillo@131
|
2510 .Pn send
|
|
meillo@131
|
2511 takes the draft folder as its default folder.
|
|
meillo@131
|
2512 .P
|
|
meillo@131
|
2513 Dropping the draft message concept in favor for the draft folder concept,
|
|
meillo@131
|
2514 removed special cases with regular cases.
|
|
meillo@131
|
2515 This simplified the source code of the tools, as well as the concepts.
|
|
meillo@131
|
2516 In mmh, draft management does not break with the MH concepts
|
|
meillo@131
|
2517 but applies them.
|
|
meillo@133
|
2518 .Cl "scan +drafts" ,
|
|
meillo@133
|
2519 for instance, is a truly natural request.
|
|
meillo@131
|
2520 Most of the work was already done by Rose in the eighties.
|
|
meillo@133
|
2521 The original improvement of mmh is dropping the old draft message approach
|
|
meillo@133
|
2522 and thus simplifying the tools, the documentation and the system as a whole.
|
|
meillo@131
|
2523 Although my part in the draft handling improvement was small,
|
|
meillo@133
|
2524 it was an important one.
|
|
meillo@131
|
2525
|
|
meillo@131
|
2526
|
|
meillo@131
|
2527 .U3 "Trash Folder
|
|
meillo@131
|
2528 .P
|
|
meillo@131
|
2529 Similar to the situation for drafts is the situation for removed messages.
|
|
meillo@131
|
2530 Historically, a message was ``deleted'' by prepending a specific
|
|
meillo@131
|
2531 \fIbackup prefix\fP, usually the comma character,
|
|
meillo@131
|
2532 to the file name.
|
|
meillo@131
|
2533 The specific message would vanish from MH because only files with
|
|
meillo@131
|
2534 non-digit characters in their name are not treated as messages.
|
|
meillo@131
|
2535 Although files remained in the file system,
|
|
meillo@131
|
2536 the messages were no more visible in MH.
|
|
meillo@131
|
2537 To truly delete them, a maintenance job is needed.
|
|
meillo@131
|
2538 Usually a cron job is installed to delete them after a grace time.
|
|
meillo@131
|
2539 For instance:
|
|
meillo@131
|
2540 .VS
|
|
meillo@131
|
2541 find $HOME/Mail -type f -name ',*' -ctime +7 -delete
|
|
meillo@131
|
2542 VE
|
|
meillo@131
|
2543 In such a setup, the original message can be restored
|
|
meillo@131
|
2544 within the grace time interval by stripping the
|
|
meillo@131
|
2545 the backup prefix from the file name.
|
|
meillo@131
|
2546 But one can not rely on this statement.
|
|
meillo@131
|
2547 If the last message of a folder with six messages (1-6) is removed,
|
|
meillo@131
|
2548 message
|
|
meillo@131
|
2549 .Fn 6 ,
|
|
meillo@131
|
2550 becomes file
|
|
meillo@131
|
2551 .Fn ,6 .
|
|
meillo@131
|
2552 If then a new message enters the same folder, it will be given
|
|
meillo@131
|
2553 the number one higher than the highest existing message.
|
|
meillo@131
|
2554 In this case the message is named
|
|
meillo@131
|
2555 .Fn 6
|
|
meillo@131
|
2556 then.
|
|
meillo@131
|
2557 If this message is removed as well,
|
|
meillo@131
|
2558 then the backup of the former message gets overwritten.
|
|
meillo@131
|
2559 Hence, the ability to restore removed messages does not only depend on
|
|
meillo@131
|
2560 the ``sweeping cron job'' but also on the removing of further messages.
|
|
meillo@131
|
2561 It is undesirable to have such obscure and complex mechanisms.
|
|
meillo@131
|
2562 The user should be given a small set of clear assertions.
|
|
meillo@131
|
2563 ``Removed files are restorable within a seven-day grace time.''
|
|
meillo@131
|
2564 is such a clear assertion.
|
|
meillo@131
|
2565 With the addition ``... unless a message with the same name in the
|
|
meillo@131
|
2566 same folder is removed before.'' the statement becomes complex.
|
|
meillo@131
|
2567 A user will hardly be able to keep track of any removal to know
|
|
meillo@131
|
2568 if the assertion still holds true for a specific file.
|
|
meillo@131
|
2569 The the real mechanism is practically obscure to the user.
|
|
meillo@131
|
2570 The consequences of further removals are not obvious.
|
|
meillo@131
|
2571 .P
|
|
meillo@131
|
2572 Further more, the backup files are scattered within the whole mail storage.
|
|
meillo@131
|
2573 This complicates managing them.
|
|
meillo@131
|
2574 It is possible, with help of
|
|
meillo@131
|
2575 .Pn find ,
|
|
meillo@131
|
2576 but everything would be more convenient
|
|
meillo@131
|
2577 if the deleted messages would be collected in one place.
|
|
meillo@131
|
2578 .P
|
|
meillo@131
|
2579 The profile entry
|
|
meillo@131
|
2580 .Pe rmmproc
|
|
meillo@131
|
2581 (previously named
|
|
meillo@131
|
2582 .Pe Delete-Prog )
|
|
meillo@131
|
2583 was introduced very early to improve the situation.
|
|
meillo@131
|
2584 It could be set to any command, which would be executed to removed
|
|
meillo@131
|
2585 the specified messages.
|
|
meillo@131
|
2586 This would override the default action, described above.
|
|
meillo@131
|
2587 Refiling the to-be-removed files to a garbage folder is the usual example.
|
|
meillo@131
|
2588 Nmh's man page
|
|
meillo@131
|
2589 .Mp rmm (1)
|
|
meillo@131
|
2590 proposes to set the
|
|
meillo@131
|
2591 .Pe rmmproc
|
|
meillo@131
|
2592 to
|
|
meillo@131
|
2593 .Cl "refile +d
|
|
meillo@131
|
2594 to move messages to the garbage folder,
|
|
meillo@131
|
2595 .Fn +d ,
|
|
meillo@131
|
2596 instead of renaming them with the backup prefix.
|
|
meillo@131
|
2597 The man page proposes additionally the expunge command
|
|
meillo@131
|
2598 .Cl "rm `mhpath +d all`
|
|
meillo@131
|
2599 to empty the garbage folder.
|
|
meillo@131
|
2600 .P
|
|
meillo@131
|
2601 Removing messages in such a way has advantages.
|
|
meillo@131
|
2602 The mail storage is prevented from being cluttered with removed messages
|
|
meillo@131
|
2603 because they are all collected in one place.
|
|
meillo@131
|
2604 Existing and removed messages are thus separated more strictly.
|
|
meillo@131
|
2605 No backup files are silently overwritten.
|
|
meillo@131
|
2606 Most important is the ability to keep removed messages in the MH domain.
|
|
meillo@131
|
2607 Messages in the trash folder can be listed like those in any other folder.
|
|
meillo@131
|
2608 Deleted messages can be displayed like any other messages.
|
|
meillo@131
|
2609 Restoring a deleted messages can be done with
|
|
meillo@131
|
2610 .Pn refile .
|
|
meillo@131
|
2611 All operations on deleted files are still covered by the MH tools.
|
|
meillo@131
|
2612 The trash folder is just like any other folder in the mail storage.
|
|
meillo@131
|
2613 .P
|
|
meillo@131
|
2614 Similar to the draft folder case, I dropped the old backup prefix approach
|
|
meillo@131
|
2615 in favor for replacing it by the better suiting trash folder system.
|
|
meillo@131
|
2616 Hence,
|
|
meillo@131
|
2617 .Pn rmm
|
|
meillo@131
|
2618 calls
|
|
meillo@131
|
2619 .Pn refile
|
|
meillo@131
|
2620 to move the to-be-removed message to the trash folder,
|
|
meillo@131
|
2621 .Fn +trash
|
|
meillo@131
|
2622 by default.
|
|
meillo@131
|
2623 To sweep it clean, one can use
|
|
meillo@131
|
2624 .Cl "rmm -unlink +trash a" ,
|
|
meillo@131
|
2625 where the
|
|
meillo@131
|
2626 .Sw -unlink
|
|
meillo@131
|
2627 switch causes the files to be unlinked.
|
|
meillo@131
|
2628 .P
|
|
meillo@131
|
2629 Dropping the legacy approach and completely converting to the new approach
|
|
meillo@131
|
2630 simplified the code base.
|
|
meillo@131
|
2631 The relationship between
|
|
meillo@131
|
2632 .Pn rmm
|
|
meillo@131
|
2633 and
|
|
meillo@131
|
2634 .Pn refile
|
|
meillo@131
|
2635 was inverted.
|
|
meillo@131
|
2636 In mmh,
|
|
meillo@131
|
2637 .Pn rmm
|
|
meillo@131
|
2638 invokes
|
|
meillo@131
|
2639 .Pn refile ,
|
|
meillo@131
|
2640 which used to be the other way round.
|
|
meillo@131
|
2641 Yet, the relationship is simpler now.
|
|
meillo@131
|
2642 No more can loops, like described in nmh's man page for
|
|
meillo@131
|
2643 .Mp refile (1),
|
|
meillo@131
|
2644 occur:
|
|
meillo@131
|
2645 .QS
|
|
meillo@131
|
2646 Since
|
|
meillo@131
|
2647 .Pn refile
|
|
meillo@131
|
2648 uses your
|
|
meillo@131
|
2649 .Pe rmmproc
|
|
meillo@131
|
2650 to delete the message, the
|
|
meillo@131
|
2651 .Pe rmmproc
|
|
meillo@131
|
2652 must NOT call
|
|
meillo@131
|
2653 .Pn refile
|
|
meillo@131
|
2654 without specifying
|
|
meillo@131
|
2655 .Sw -normmproc
|
|
meillo@131
|
2656 or you will create an infinite loop.
|
|
meillo@131
|
2657 .QE
|
|
meillo@131
|
2658 .LP
|
|
meillo@131
|
2659 .Pn rmm
|
|
meillo@131
|
2660 either unlinks a message with
|
|
meillo@131
|
2661 .Fu unlink()
|
|
meillo@131
|
2662 or invokes
|
|
meillo@131
|
2663 .Pn refile
|
|
meillo@131
|
2664 to move it to the trash folder.
|
|
meillo@131
|
2665 .Pn refile
|
|
meillo@131
|
2666 does not invoke any tools.
|
|
meillo@131
|
2667 .P
|
|
meillo@131
|
2668
|
|
meillo@131
|
2669
|
|
meillo@131
|
2670
|
|
meillo@131
|
2671 Keeping unused alternative in the code is a bad choice as they likely
|
|
meillo@131
|
2672 gather bugs, by not being constantly tested.
|
|
meillo@131
|
2673 Also, the increased code
|
|
meillo@131
|
2674 size and more conditions crease the maintenance costs.
|
|
meillo@131
|
2675
|
|
meillo@131
|
2676 By generalizing the message removal in a way that it becomes covered
|
|
meillo@131
|
2677 by the MH concepts makes the whole system more powerful.
|
|
meillo@131
|
2678
|
|
meillo@131
|
2679
|
|
meillo@131
|
2680
|
|
meillo@131
|
2681
|
|
meillo@133
|
2682 .H2 "Modern Defaults
|
|
meillo@133
|
2683 .P
|
|
meillo@133
|
2684 Nmh has a bunch of convenience-improving features inactive by default,
|
|
meillo@133
|
2685 although one can expect every new user wanting to have them active.
|
|
meillo@133
|
2686 The reason they are inactive by default is the wish to stay compatible
|
|
meillo@133
|
2687 with old versions.
|
|
meillo@133
|
2688 But what is the definition for old versions.
|
|
meillo@133
|
2689 Still, the highly useful draft folder facility is not active by default
|
|
meillo@133
|
2690 although it had been introduced over twenty-five years ago
|
|
meillo@133
|
2691 .[
|
|
meillo@133
|
2692 rose romine real work
|
|
meillo@133
|
2693 .]
|
|
meillo@133
|
2694 \(en the community seems not to care.
|
|
meillo@133
|
2695 This is one of several examples that require new users to build up
|
|
meillo@133
|
2696 their profile before they can access the modern features of nmh.
|
|
meillo@133
|
2697 Without an extensively built-up profile, the setup is hardly usable
|
|
meillo@133
|
2698 for modern emailing.
|
|
meillo@133
|
2699 The point is not the customization of the setup,
|
|
meillo@133
|
2700 but the activating of generally useful facilities.
|
|
meillo@133
|
2701 .P
|
|
meillo@133
|
2702 Yet, the real problem lies less in enabling the features, as this is
|
|
meillo@133
|
2703 straight forward as soon as one knows what he wants.
|
|
meillo@133
|
2704 The real problem is that new users need deep insights into the project
|
|
meillo@133
|
2705 before they find out what they are missing and that nmh actually
|
|
meillo@133
|
2706 provides it already, it just was not activated.
|
|
meillo@133
|
2707 To give an example, I needed one year of using nmh
|
|
meillo@133
|
2708 before I became aware of the existence of the attachment system.
|
|
meillo@133
|
2709 One could argue that this fact disqualifies my reading of the
|
|
meillo@133
|
2710 documentation.
|
|
meillo@133
|
2711 If I would have installed nmh from source back then, I could agree.
|
|
meillo@133
|
2712 Yet, I had used a prepackaged version and had expected that it would
|
|
meillo@133
|
2713 just work.
|
|
meillo@133
|
2714 Nevertheless, I had been convinced by the concepts of MH already
|
|
meillo@133
|
2715 and I am a software developer,
|
|
meillo@133
|
2716 still I required a lot of time to discover the cool features.
|
|
meillo@133
|
2717 How can we expect users to be even more advanced than me,
|
|
meillo@133
|
2718 just to allow them use MH in a convenient and modern way?
|
|
meillo@133
|
2719 Unless they are strongly convinced of the concepts, they will fail.
|
|
meillo@133
|
2720 I have seen friends of me giving up disappointed
|
|
meillo@133
|
2721 before they truly used the system,
|
|
meillo@133
|
2722 although they had been motivated in the beginning.
|
|
meillo@133
|
2723 They suffer hard enough to get used to the toolchest approach,
|
|
meillo@133
|
2724 we should spare them further inconveniences.
|
|
meillo@133
|
2725 .P
|
|
meillo@133
|
2726 Maintaining compatibility for its own sake is for no good.
|
|
meillo@133
|
2727 If any MH implementation would be the back-end of widespread
|
|
meillo@133
|
2728 email clients with large user bases, compatibility would be more
|
|
meillo@133
|
2729 important.
|
|
meillo@133
|
2730 Yet, it appears as if this is not the case.
|
|
meillo@133
|
2731 Hence, compatibility is hardly important for technical reasons.
|
|
meillo@133
|
2732 Its importance originates rather from personal reasons.
|
|
meillo@133
|
2733 Nmh's user base is small and old.
|
|
meillo@133
|
2734 Changing the interfaces would cause inconvenience to long-term users of MH.
|
|
meillo@133
|
2735 It would force them to change their many years old MH configurations.
|
|
meillo@133
|
2736 I do understand this aspect, but it keeps new users from using MH.
|
|
meillo@133
|
2737 By sticking to the old users, new users are kept away.
|
|
meillo@133
|
2738 Yet, the future lies in new users.
|
|
meillo@133
|
2739 Hence, mmh invites new users by providing a convenient and modern setup,
|
|
meillo@133
|
2740 readily usable out-of-the-box.
|
|
meillo@133
|
2741 .P
|
|
meillo@133
|
2742 In mmh, all modern features are active by default.
|
|
meillo@133
|
2743 In consequence, a setup with a profile that defines only the path to the
|
|
meillo@133
|
2744 mail storage, is already convenient to use.
|
|
meillo@133
|
2745 Again, Paul Vixie's ``edginess'' appeal supports the direction I took:
|
|
meillo@133
|
2746 ``the `main branch' should just be modern''.
|
|
meillo@133
|
2747 .[
|
|
meillo@133
|
2748 paul vixie edginess nmh-workers
|
|
meillo@133
|
2749 .]
|
|
meillo@133
|
2750 .P
|
|
meillo@133
|
2751 Modern features that are active in mmh by default include:
|
|
meillo@133
|
2752 .BU
|
|
meillo@133
|
2753 The attachment system (\c
|
|
meillo@133
|
2754 .Hd Attach ).
|
|
meillo@133
|
2755 .Ci 8ff284ff9167eff8f5349481529332d59ed913b1
|
|
meillo@133
|
2756 .BU
|
|
meillo@133
|
2757 The draft folder facility (\c
|
|
meillo@133
|
2758 .Fn +drafts ).
|
|
meillo@133
|
2759 .Ci 337338b404931f06f0db2119c9e145e8ca5a9860
|
|
meillo@133
|
2760 .BU
|
|
meillo@133
|
2761 The unseen sequence (`u')
|
|
meillo@133
|
2762 .Ci c2360569e1d8d3678e294eb7c1354cb8bf7501c1
|
|
meillo@133
|
2763 and the sequence negation prefix (`!').
|
|
meillo@133
|
2764 .Ci db74c2bd004b2dc9bf8086a6d8bf773ac051f3cc
|
|
meillo@133
|
2765 .BU
|
|
meillo@133
|
2766 Quoting the original message in the reply.
|
|
meillo@133
|
2767 .Ci 67411b1f95d6ec987b4c732459e1ba8a8ac192c6
|
|
meillo@133
|
2768 .BU
|
|
meillo@133
|
2769 Forwarding messages using MIME.
|
|
meillo@133
|
2770 .Ci 6e271608b7b9c23771523f88d23a4d3593010cf1
|
|
meillo@131
|
2771
|
|
meillo@133
|
2772
|
|
meillo@133
|
2773
|
|
meillo@133
|
2774
|
|
meillo@133
|
2775
|
|
meillo@133
|
2776 .\" --------------------------------------------------------------
|
|
meillo@131
|
2777 .H1 "Styling
|
|
meillo@22
|
2778 .P
|
|
meillo@118
|
2779 Kernighan and Pike have emphasized the importance of style in the
|
|
meillo@118
|
2780 preface of their book:
|
|
meillo@118
|
2781 .[ [
|
|
meillo@118
|
2782 kernighan pike practice of programming
|
|
meillo@118
|
2783 .], p. x]
|
|
meillo@118
|
2784 .QS
|
|
meillo@118
|
2785 Chapter 1 discusses programming style.
|
|
meillo@118
|
2786 Good style is so important to good programming that we have chose
|
|
meillo@118
|
2787 to cover it first.
|
|
meillo@118
|
2788 .QE
|
|
meillo@118
|
2789 This section covers changes in mmh that were motivated by the desire
|
|
meillo@118
|
2790 to improve on style.
|
|
meillo@118
|
2791 Many of them follow the rules given in the quoted book.
|
|
meillo@118
|
2792 .[
|
|
meillo@118
|
2793 kernighan pike practice of programming
|
|
meillo@118
|
2794 .]
|
|
meillo@118
|
2795
|
|
meillo@118
|
2796
|
|
meillo@127
|
2797
|
|
meillo@127
|
2798
|
|
meillo@127
|
2799 .H2 "Code Style
|
|
meillo@118
|
2800 .P
|
|
meillo@118
|
2801 .U3 "Indentation Style
|
|
meillo@118
|
2802 .P
|
|
meillo@118
|
2803 Indentation styles are the holy cow of programmers.
|
|
meillo@118
|
2804 Again Kernighan and Pike:
|
|
meillo@118
|
2805 .[ [
|
|
meillo@118
|
2806 kernighan pike practice of programming
|
|
meillo@118
|
2807 .], p. 10]
|
|
meillo@118
|
2808 .QS
|
|
meillo@118
|
2809 Programmers have always argued about the layout of programs,
|
|
meillo@118
|
2810 but the specific style is much less important than its consistent
|
|
meillo@118
|
2811 application.
|
|
meillo@121
|
2812 Pick one style, preferably ours, use it consistently, and don't waste
|
|
meillo@118
|
2813 time arguing.
|
|
meillo@118
|
2814 .QE
|
|
meillo@118
|
2815 .P
|
|
meillo@118
|
2816 I agree that the constant application is most important,
|
|
meillo@118
|
2817 but I believe that some styles have advantages over others.
|
|
meillo@118
|
2818 For instance the indentation with tab characters only.
|
|
meillo@118
|
2819 Tab characters directly map to the nesting level \(en
|
|
meillo@118
|
2820 one tab, one level.
|
|
meillo@118
|
2821 Tab characters are flexible because developers can adjust them to
|
|
meillo@118
|
2822 whatever width they like to have.
|
|
meillo@118
|
2823 There is no more need to run
|
|
meillo@118
|
2824 .Pn unexpand
|
|
meillo@118
|
2825 or
|
|
meillo@118
|
2826 .Pn entab
|
|
meillo@118
|
2827 programs to ensure the correct mixture of leading tabs and spaces.
|
|
meillo@118
|
2828 The simple rules are: (1) Leading whitespace must consist of tabs only.
|
|
meillo@118
|
2829 (2) Any other whitespace should consist of spaces.
|
|
meillo@121
|
2830 These two rules ensure the integrity of the visual appearance.
|
|
meillo@121
|
2831 Although reformatting existing code should be avoided, I did it.
|
|
meillo@118
|
2832 I did not waste time arguing; I just did it.
|
|
meillo@118
|
2833 .Ci a485ed478abbd599d8c9aab48934e7a26733ecb1
|
|
meillo@118
|
2834
|
|
meillo@118
|
2835 .U3 "Comments
|
|
meillo@118
|
2836 .P
|
|
meillo@118
|
2837 Section 1.6 of
|
|
meillo@118
|
2838 .[ [
|
|
meillo@118
|
2839 kernighan pike practice of programming
|
|
meillo@118
|
2840 .], p. 23]
|
|
meillo@118
|
2841 demands: ``Don't belabor the obvious.''
|
|
meillo@122
|
2842 Hence, I simply removed all the comments in the following code excerpt:
|
|
meillo@118
|
2843 .VS
|
|
meillo@120
|
2844 context_replace(curfolder, folder); /* update current folder */
|
|
meillo@120
|
2845 seq_setcur(mp, mp->lowsel); /* update current message */
|
|
meillo@120
|
2846 seq_save(mp); /* synchronize message sequences */
|
|
meillo@120
|
2847 folder_free(mp); /* free folder/message structure */
|
|
meillo@120
|
2848 context_save(); /* save the context file */
|
|
meillo@120
|
2849
|
|
meillo@120
|
2850 [...]
|
|
meillo@120
|
2851
|
|
meillo@120
|
2852 int c; /* current character */
|
|
meillo@120
|
2853 char *cp; /* miscellaneous character pointer */
|
|
meillo@120
|
2854
|
|
meillo@120
|
2855 [...]
|
|
meillo@120
|
2856
|
|
meillo@120
|
2857 /* NUL-terminate the field */
|
|
meillo@120
|
2858 *cp = '\0';
|
|
meillo@118
|
2859 VE
|
|
meillo@120
|
2860 .Ci 426543622b377fc5d091455cba685e114b6df674
|
|
meillo@118
|
2861 .P
|
|
meillo@118
|
2862 The names of the functions explain enough already.
|
|
meillo@118
|
2863
|
|
meillo@118
|
2864 .U3 "Names
|
|
meillo@118
|
2865 .P
|
|
meillo@118
|
2866 Kernighan and Pike suggest:
|
|
meillo@118
|
2867 ``Use active names for functions''.
|
|
meillo@118
|
2868 .[ [
|
|
meillo@118
|
2869 kernighan pike practice of programming
|
|
meillo@118
|
2870 .], p. 4]
|
|
meillo@118
|
2871 One application of this rule was the rename of
|
|
meillo@118
|
2872 .Fu check_charset()
|
|
meillo@118
|
2873 to
|
|
meillo@118
|
2874 .Fu is_native_charset() .
|
|
meillo@118
|
2875 .Ci 8d77b48284c58c135a6b2787e721597346ab056d
|
|
meillo@118
|
2876 The same change fixed a violation of ``Be accurate'' as well.
|
|
meillo@118
|
2877 The code did not match the expectation the function suggested,
|
|
meillo@118
|
2878 as it, for whatever reason, only compared the first ten characters
|
|
meillo@118
|
2879 of the charset name.
|
|
meillo@118
|
2880 .P
|
|
meillo@118
|
2881 More important than using active names is using descriptive names.
|
|
meillo@118
|
2882 Renaming the obscure function
|
|
meillo@118
|
2883 .Fu m_unknown()
|
|
meillo@118
|
2884 was a delightful event.
|
|
meillo@118
|
2885 .Ci 611d68d19204d7cbf5bd585391249cb5bafca846
|
|
meillo@118
|
2886 .P
|
|
meillo@118
|
2887 Magic numbers are generally considered bad style.
|
|
meillo@118
|
2888 Obviously, Kernighan and Pike agree:
|
|
meillo@118
|
2889 ``Give names to magic numbers''.
|
|
meillo@118
|
2890 .[ [
|
|
meillo@118
|
2891 kernighan pike practice of programming
|
|
meillo@118
|
2892 .], p. 19]
|
|
meillo@118
|
2893 One such change was naming the type of input \(en mbox or mail folder \(en
|
|
meillo@118
|
2894 to be scanned:
|
|
meillo@118
|
2895 .VS
|
|
meillo@118
|
2896 #define SCN_MBOX (-1)
|
|
meillo@118
|
2897 #define SCN_FOLD 0
|
|
meillo@118
|
2898 VE
|
|
meillo@118
|
2899 .Ci 7ffb36d28e517a6f3a10272056fc127592ab1c19
|
|
meillo@118
|
2900 .P
|
|
meillo@118
|
2901 The argument
|
|
meillo@118
|
2902 .Ar outnum
|
|
meillo@118
|
2903 of the function
|
|
meillo@118
|
2904 .Fu scan()
|
|
meillo@118
|
2905 in
|
|
meillo@118
|
2906 .Fn uip/scansbr.c
|
|
meillo@118
|
2907 defines the number of the message to be created.
|
|
meillo@118
|
2908 If no message is to be created, the argument is misused to transport
|
|
meillo@118
|
2909 program logic.
|
|
meillo@118
|
2910 This lead to obscure code.
|
|
meillo@118
|
2911 I improved the clarity of the code by introducing two variables:
|
|
meillo@118
|
2912 .VS
|
|
meillo@118
|
2913 int incing = (outnum > 0);
|
|
meillo@118
|
2914 int ismbox = (outnum != 0);
|
|
meillo@118
|
2915 VE
|
|
meillo@118
|
2916 They cover the magic values and are used for conditions.
|
|
meillo@118
|
2917 The variable
|
|
meillo@118
|
2918 .Ar outnum
|
|
meillo@118
|
2919 is only used when it holds an ordinary message number.
|
|
meillo@118
|
2920 .Ci b8b075c77be7794f3ae9ff0e8cedb12b48fd139f
|
|
meillo@118
|
2921 The clarity improvement of the change showed detours in the program logic
|
|
meillo@118
|
2922 of related code parts.
|
|
meillo@118
|
2923 Having the new variables with descriptive names, a more
|
|
meillo@121
|
2924 straight forward implementation became apparent.
|
|
meillo@118
|
2925 Before the clarification was done,
|
|
meillo@118
|
2926 the possibility to improve had not be seen.
|
|
meillo@118
|
2927 .Ci aa60b0ab5e804f8befa890c0a6df0e3143ce0723
|
|
meillo@118
|
2928
|
|
meillo@133
|
2929
|
|
meillo@133
|
2930
|
|
meillo@133
|
2931 .H2 "Structural Rework
|
|
meillo@133
|
2932 .P
|
|
meillo@133
|
2933
|
|
meillo@118
|
2934 .U3 "Rework of \f(CWanno\fP
|
|
meillo@118
|
2935 .P
|
|
meillo@118
|
2936 At the end of their chapter on style,
|
|
meillo@118
|
2937 Kernighan and Pike ask: ``But why worry about style?''
|
|
meillo@121
|
2938 The following example of my rework of
|
|
meillo@118
|
2939 .Pn anno
|
|
meillo@121
|
2940 provides an answer why style is important in the first place.
|
|
meillo@118
|
2941 .P
|
|
meillo@120
|
2942 Until 2002,
|
|
meillo@120
|
2943 .Pn anno
|
|
meillo@120
|
2944 had six functional command line switches,
|
|
meillo@120
|
2945 .Sw -component
|
|
meillo@120
|
2946 and
|
|
meillo@120
|
2947 .Sw -text ,
|
|
meillo@120
|
2948 which took an argument each,
|
|
meillo@120
|
2949 and the two pairs of flags,
|
|
meillo@120
|
2950 .Sw -[no]date
|
|
meillo@120
|
2951 and
|
|
meillo@120
|
2952 .Sw -[no]inplace.,
|
|
meillo@120
|
2953 .Sw -component
|
|
meillo@120
|
2954 and
|
|
meillo@120
|
2955 .Sw -text ,
|
|
meillo@120
|
2956 which took an argument each,
|
|
meillo@120
|
2957 and the two pairs of flags,
|
|
meillo@120
|
2958 .Sw -[no]date
|
|
meillo@120
|
2959 and
|
|
meillo@120
|
2960 .Sw -[no]inplace .
|
|
meillo@120
|
2961 Then Jon Steinhart introduced his attachment system.
|
|
meillo@120
|
2962 In need for more advanced annotation handling, he extended
|
|
meillo@120
|
2963 .Pn anno .
|
|
meillo@120
|
2964 He added five more switches:
|
|
meillo@120
|
2965 .Sw -draft ,
|
|
meillo@120
|
2966 .Sw -list ,
|
|
meillo@120
|
2967 .Sw -delete ,
|
|
meillo@120
|
2968 .Sw -append ,
|
|
meillo@120
|
2969 and
|
|
meillo@120
|
2970 .Sw -number ,
|
|
meillo@120
|
2971 the last one taking an argument.
|
|
meillo@121
|
2972 .Ci 7480dbc14bc90f2d872d434205c0784704213252
|
|
meillo@120
|
2973 Later,
|
|
meillo@120
|
2974 .Sw -[no]preserve
|
|
meillo@120
|
2975 was added.
|
|
meillo@121
|
2976 .Ci d9b1d57351d104d7ec1a5621f090657dcce8cb7f
|
|
meillo@120
|
2977 Then, the Synopsis section of the man page
|
|
meillo@120
|
2978 .Mp anno (1)
|
|
meillo@120
|
2979 read:
|
|
meillo@120
|
2980 .VS
|
|
meillo@120
|
2981 anno [+folder] [msgs] [-component field] [-inplace | -noinplace]
|
|
meillo@120
|
2982 [-date | -nodate] [-draft] [-append] [-list] [-delete]
|
|
meillo@120
|
2983 [-number [num|all]] [-preserve | -nopreserve] [-version]
|
|
meillo@120
|
2984 [-help] [-text body]
|
|
meillo@120
|
2985 VE
|
|
meillo@120
|
2986 .LP
|
|
meillo@120
|
2987 The implementation followed the same structure.
|
|
meillo@120
|
2988 Problems became visible when
|
|
meillo@120
|
2989 .Cl "anno -list -number 42
|
|
meillo@120
|
2990 worked on the current message instead on message number 42,
|
|
meillo@120
|
2991 and
|
|
meillo@120
|
2992 .Cl "anno -list -number l:5
|
|
meillo@124
|
2993 did not work on the last five messages but failed with the mysterious
|
|
meillo@120
|
2994 error message: ``anno: missing argument to -list''.
|
|
meillo@121
|
2995 Yet, the invocation matched the specification in the man page.
|
|
meillo@120
|
2996 There, the correct use of
|
|
meillo@120
|
2997 .Sw -number
|
|
meillo@120
|
2998 was defined as being
|
|
meillo@120
|
2999 .Cl "[-number [num|all]]
|
|
meillo@120
|
3000 and the textual description for the combination with
|
|
meillo@120
|
3001 .Sw -list
|
|
meillo@120
|
3002 read:
|
|
meillo@120
|
3003 .QS
|
|
meillo@120
|
3004 The -list option produces a listing of the field bodies for
|
|
meillo@120
|
3005 header fields with names matching the specified component,
|
|
meillo@120
|
3006 one per line. The listing is numbered, starting at 1, if
|
|
meillo@120
|
3007 the -number option is also used.
|
|
meillo@120
|
3008 .QE
|
|
meillo@120
|
3009 .LP
|
|
meillo@120
|
3010 The problem was manifold.
|
|
meillo@120
|
3011 The code required a numeric argument to the
|
|
meillo@120
|
3012 .Sw -number
|
|
meillo@120
|
3013 switch.
|
|
meillo@120
|
3014 If it was missing or non-numeric,
|
|
meillo@120
|
3015 .Pn anno
|
|
meillo@120
|
3016 aborted with an error message that had an off-by-one error,
|
|
meillo@120
|
3017 printing the switch one before the failing one.
|
|
meillo@120
|
3018 Semantically, the argument to the
|
|
meillo@120
|
3019 .Sw -number
|
|
meillo@120
|
3020 switch is only necessary in combination with
|
|
meillo@120
|
3021 .Sw -delete ,
|
|
meillo@120
|
3022 but not with
|
|
meillo@120
|
3023 .Sw -list .
|
|
meillo@120
|
3024 In the former case it is even necessary.
|
|
meillo@120
|
3025 .P
|
|
meillo@120
|
3026 Trying to fix these problems on the surface would not have solved it truly.
|
|
meillo@120
|
3027 The problems discovered originate from a discrepance between the semantic
|
|
meillo@120
|
3028 structure of the problem and the structure implemented in the program.
|
|
meillo@120
|
3029 Such structural differences can not be cured on the surface.
|
|
meillo@120
|
3030 They need to be solved by adjusting the structure of the implementation
|
|
meillo@120
|
3031 to the structure of the problem.
|
|
meillo@120
|
3032 .P
|
|
meillo@120
|
3033 In 2002, the new switches
|
|
meillo@120
|
3034 .Sw -list
|
|
meillo@120
|
3035 and
|
|
meillo@120
|
3036 .Sw -delete
|
|
meillo@120
|
3037 were added in the same way, the
|
|
meillo@120
|
3038 .Sw -number
|
|
meillo@120
|
3039 switch for instance had been added.
|
|
meillo@120
|
3040 Yet, they are of structural different type.
|
|
meillo@120
|
3041 Semantically,
|
|
meillo@120
|
3042 .Sw -list
|
|
meillo@120
|
3043 and
|
|
meillo@120
|
3044 .Sw -delete
|
|
meillo@120
|
3045 introduce modes of operation.
|
|
meillo@120
|
3046 Historically,
|
|
meillo@120
|
3047 .Pn anno
|
|
meillo@120
|
3048 had only one operation mode: adding header fields.
|
|
meillo@120
|
3049 With the extension, it got two moder modes:
|
|
meillo@120
|
3050 listing and deleting header fields.
|
|
meillo@120
|
3051 The structure of the code changes did not pay respect to this
|
|
meillo@120
|
3052 fundamental change to
|
|
meillo@120
|
3053 .Pn anno 's
|
|
meillo@120
|
3054 behavior.
|
|
meillo@120
|
3055 Neither the implementation nor the documentation did clearly
|
|
meillo@120
|
3056 define them as being exclusive modes of operation.
|
|
meillo@120
|
3057 Having identified the problem, I solved it by putting structure into
|
|
meillo@120
|
3058 .Pn anno
|
|
meillo@120
|
3059 and its documentation.
|
|
meillo@120
|
3060 .Ci d54c8db8bdf01e8381890f7729bc0ef4a055ea11
|
|
meillo@120
|
3061 .P
|
|
meillo@120
|
3062 The difference is visible in both, the code and the documentation.
|
|
meillo@121
|
3063 The following code excerpt:
|
|
meillo@120
|
3064 .VS
|
|
meillo@120
|
3065 int delete = -2; /* delete header element if set */
|
|
meillo@120
|
3066 int list = 0; /* list header elements if set */
|
|
meillo@120
|
3067 [...]
|
|
meillo@121
|
3068 case DELETESW: /* delete annotations */
|
|
meillo@121
|
3069 delete = 0;
|
|
meillo@121
|
3070 continue;
|
|
meillo@121
|
3071 case LISTSW: /* produce a listing */
|
|
meillo@121
|
3072 list = 1;
|
|
meillo@121
|
3073 continue;
|
|
meillo@120
|
3074 VE
|
|
meillo@121
|
3075 .LP
|
|
meillo@121
|
3076 was replaced by:
|
|
meillo@120
|
3077 .VS
|
|
meillo@120
|
3078 static enum { MODE_ADD, MODE_DEL, MODE_LIST } mode = MODE_ADD;
|
|
meillo@120
|
3079 [...]
|
|
meillo@121
|
3080 case DELETESW: /* delete annotations */
|
|
meillo@121
|
3081 mode = MODE_DEL;
|
|
meillo@121
|
3082 continue;
|
|
meillo@121
|
3083 case LISTSW: /* produce a listing */
|
|
meillo@121
|
3084 mode = MODE_LIST;
|
|
meillo@121
|
3085 continue;
|
|
meillo@120
|
3086 VE
|
|
meillo@120
|
3087 .LP
|
|
meillo@121
|
3088 The replacement code does not only reflect the problem's structure better,
|
|
meillo@121
|
3089 it is easier to understand as well.
|
|
meillo@121
|
3090 The same applies to the documentation.
|
|
meillo@120
|
3091 The man page was completely reorganized to propagate the same structure.
|
|
meillo@121
|
3092 This is visible in the Synopsis section:
|
|
meillo@120
|
3093 .VS
|
|
meillo@120
|
3094 anno [+folder] [msgs] [-component field] [-text body]
|
|
meillo@120
|
3095 [-append] [-date | -nodate] [-preserve | -nopreserve]
|
|
meillo@120
|
3096 [-Version] [-help]
|
|
meillo@120
|
3097
|
|
meillo@120
|
3098 anno -delete [+folder] [msgs] [-component field] [-text
|
|
meillo@120
|
3099 body] [-number num | all ] [-preserve | -nopreserve]
|
|
meillo@120
|
3100 [-Version] [-help]
|
|
meillo@120
|
3101
|
|
meillo@120
|
3102 anno -list [+folder] [msgs] [-component field] [-number]
|
|
meillo@120
|
3103 [-Version] [-help]
|
|
meillo@120
|
3104 VE
|
|
meillo@121
|
3105 .\" XXX think about explaining the -preserve rework?
|
|
meillo@118
|
3106
|
|
meillo@58
|
3107
|
|
meillo@58
|
3108
|
|
meillo@133
|
3109 .U3 "Path Conversion
|
|
meillo@133
|
3110 .P
|
|
meillo@133
|
3111 FIXME! XXX
|
|
meillo@133
|
3112
|
|
meillo@133
|
3113
|
|
meillo@133
|
3114 commit d39e2c447b0d163a5a63f480b23d06edb7a73aa0
|
|
meillo@133
|
3115 Author: markus schnalke <meillo@marmaro.de>
|
|
meillo@133
|
3116 Date: Fri Dec 9 16:34:57 2011 +0100
|
|
meillo@133
|
3117
|
|
meillo@133
|
3118 Completely reworked the path convertion functions
|
|
meillo@133
|
3119 Moved everything (from sbr/getfolder.c and sbr/m_maildir.c) into
|
|
meillo@133
|
3120 sbr/path.c, but actually replaced the code almost completely.
|
|
meillo@133
|
3121 See h/prototypes.h for the function changes.
|
|
meillo@133
|
3122 sbr/path.c provides explaining comments on the functions.
|
|
meillo@133
|
3123 None of them allocates memory automatically.
|
|
meillo@133
|
3124
|
|
meillo@133
|
3125 Additionally:
|
|
meillo@133
|
3126 - Like for other ``files'', `inc -audit file' places file relative
|
|
meillo@133
|
3127 to the cwd, not relative to the mh-dir. This is for consistency.
|
|
meillo@133
|
3128 - Replaced add(foo, NULL) with getcpy(foo), which ist clearer.
|
|
meillo@133
|
3129
|
|
meillo@133
|
3130
|
|
meillo@133
|
3131
|
|
meillo@133
|
3132
|
|
meillo@133
|
3133
|
|
meillo@133
|
3134 .H2 "Profile Reading
|
|
meillo@133
|
3135 .P
|
|
meillo@133
|
3136 FIXME XXX
|
|
meillo@133
|
3137
|
|
meillo@133
|
3138 commit 3e017a7abbdf69bf0dff7a4073275961eda1ded8
|
|
meillo@133
|
3139 Author: markus schnalke <meillo@marmaro.de>
|
|
meillo@133
|
3140 Date: Wed Jun 27 14:23:35 2012 +0200
|
|
meillo@133
|
3141
|
|
meillo@133
|
3142 spost: Read profile and context now. Removed -library switch.
|
|
meillo@133
|
3143 spost is a full part of the mmh toolchest, hence, it shall read the
|
|
meillo@133
|
3144 profile/context. This will remove the need to pass profile information
|
|
meillo@133
|
3145 from send to spost via command line switches.
|
|
meillo@133
|
3146 In January 2012, there had been a discussion on the nmh-workers ML
|
|
meillo@133
|
3147 whether post should read the profile/context. There wasn't a clear
|
|
meillo@133
|
3148 answer. It behavior was mainly motivated by the historic situation,
|
|
meillo@133
|
3149 it seems. My opinion on the topic goes into the direction that every
|
|
meillo@133
|
3150 tool that is part of the mmh toolchest should read the profile. That
|
|
meillo@133
|
3151 is a clear and simple concept. Using MH tools without wanting to
|
|
meillo@133
|
3152 interact with MH (like mhmail had been) is no more a practical problem.
|
|
meillo@133
|
3153
|
|
meillo@133
|
3154 commit 32d4f9daaa70519be3072479232ff7be0500d009
|
|
meillo@133
|
3155 Author: markus schnalke <meillo@marmaro.de>
|
|
meillo@133
|
3156 Date: Wed Jun 27 13:15:47 2012 +0200
|
|
meillo@133
|
3157
|
|
meillo@133
|
3158 mhmail: Read the context!
|
|
meillo@133
|
3159 mhmail will change from a mailx-replacment to an alternative to
|
|
meillo@133
|
3160 `comp -ed prompter', thus being a send front-end. Hence, mhmail
|
|
meillo@133
|
3161 should not stay outside the profile/context respecting mmh toolchest.
|
|
meillo@133
|
3162
|
|
meillo@133
|
3163
|
|
meillo@133
|
3164 slocal
|
|
meillo@133
|
3165
|
|
meillo@133
|
3166
|
|
meillo@133
|
3167
|
|
meillo@127
|
3168
|
|
meillo@121
|
3169 .H2 "Standard Libraries
|
|
meillo@22
|
3170 .P
|
|
meillo@121
|
3171 MH is one decade older than the POSIX and ANSI C standards.
|
|
meillo@121
|
3172 Hence, MH included own implementations of functions
|
|
meillo@121
|
3173 that are standardized and thus widely available today,
|
|
meillo@121
|
3174 but were not back then.
|
|
meillo@121
|
3175 Today, twenty years after the POSIX and ANSI C were published,
|
|
meillo@121
|
3176 developers can expect system to comply with these standards.
|
|
meillo@121
|
3177 In consequence, MH-specific replacements for standard functions
|
|
meillo@121
|
3178 can and should be dropped.
|
|
meillo@121
|
3179 Kernighan and Pike advise: ``Use standard libraries.''
|
|
meillo@121
|
3180 .[ [
|
|
meillo@121
|
3181 kernighan pike practice of programming
|
|
meillo@121
|
3182 .], p. 196]
|
|
meillo@121
|
3183 Actually, MH had followed this advice in history,
|
|
meillo@121
|
3184 but it had not adjusted to the changes in this field.
|
|
meillo@121
|
3185 The
|
|
meillo@121
|
3186 .Fu snprintf()
|
|
meillo@121
|
3187 function, for instance, was standardized with C99 and is available
|
|
meillo@121
|
3188 almost everywhere because of its high usefulness.
|
|
meillo@123
|
3189 In project's own implementation of
|
|
meillo@121
|
3190 .Fu snprintf()
|
|
meillo@123
|
3191 was dropped in March 2012 in favor for using the one of the
|
|
meillo@123
|
3192 standard library.
|
|
meillo@123
|
3193 .Ci 0052f1024deb0a0a2fc2e5bacf93d45a5a9c9b32
|
|
meillo@123
|
3194 Such decisions limit the portability of mmh
|
|
meillo@121
|
3195 if systems don't support these standardized and widespread functions.
|
|
meillo@123
|
3196 This compromise is made because mmh focuses on the future.
|
|
meillo@121
|
3197 .P
|
|
meillo@123
|
3198 I am not yet thirty years old and my C and Unix experience comprises
|
|
meillo@123
|
3199 only half a dozen years.
|
|
meillo@121
|
3200 Hence, I need to learn about the history in retrospective.
|
|
meillo@121
|
3201 I have not used those ancient constructs myself.
|
|
meillo@121
|
3202 I have not suffered from their incompatibilities.
|
|
meillo@121
|
3203 I have not longed for standardization.
|
|
meillo@121
|
3204 All my programming experience is from a time when ANSI C and POSIX
|
|
meillo@121
|
3205 were well established already.
|
|
meillo@121
|
3206 I have only read a lot of books about the (good) old times.
|
|
meillo@121
|
3207 This puts me in a difficult positions when working with old code.
|
|
meillo@123
|
3208 I need to freshly acquire knowledge about old code constructs and ancient
|
|
meillo@123
|
3209 programming styles, whereas older programmers know these things by
|
|
meillo@123
|
3210 heart from their own experience.
|
|
meillo@121
|
3211 .P
|
|
meillo@123
|
3212 Being aware of the situation, I rather let people with more historic
|
|
meillo@123
|
3213 experience replace ancient code constructs with standardized ones.
|
|
meillo@121
|
3214 Lyndon Nerenberg covered large parts of this task for the nmh project.
|
|
meillo@121
|
3215 He converted project-specific functions to POSIX replacements,
|
|
meillo@121
|
3216 also removing the conditionals compilation of now standardized features.
|
|
meillo@123
|
3217 Ken Hornstein and David Levine had their part in the work, too.
|
|
meillo@121
|
3218 Often, I only needed to pull over changes from nmh into mmh.
|
|
meillo@121
|
3219 These changes include many commits; these are among them:
|
|
meillo@121
|
3220 .Ci 768b5edd9623b7238e12ec8dfc409b82a1ed9e2d
|
|
meillo@121
|
3221 .Ci 0052f1024deb0a0a2fc2e5bacf93d45a5a9c9b32 .
|
|
meillo@102
|
3222 .P
|
|
meillo@123
|
3223 During my own work, I tidied up the \fIMH standard library\fP,
|
|
meillo@123
|
3224 .Fn libmh.a ,
|
|
meillo@123
|
3225 which is located in the
|
|
meillo@123
|
3226 .Fn sbr
|
|
meillo@123
|
3227 (``subroutines'') directory in the source tree.
|
|
meillo@123
|
3228 The MH library includes functions that mmh tools usually need.
|
|
meillo@123
|
3229 Among them are MH-specific functions for profile, context, sequence,
|
|
meillo@123
|
3230 and folder handling, but as well
|
|
meillo@123
|
3231 MH-independent functions, such as auxiliary string functions,
|
|
meillo@123
|
3232 portability interfaces and error-checking wrappers for critical
|
|
meillo@123
|
3233 functions of the standard library.
|
|
meillo@123
|
3234 .P
|
|
meillo@123
|
3235 I have replaced the
|
|
meillo@121
|
3236 .Fu atooi()
|
|
meillo@121
|
3237 function with calls to
|
|
meillo@123
|
3238 .Fu strtoul()
|
|
meillo@121
|
3239 with the third parameter \(en the base \(en set to eight.
|
|
meillo@121
|
3240 .Fu strtoul()
|
|
meillo@123
|
3241 is part of C89 and thus considered safe to use.
|
|
meillo@121
|
3242 .Ci c490c51b3c0f8871b6953bd0c74551404f840a74
|
|
meillo@102
|
3243 .P
|
|
meillo@121
|
3244 I did remove project-included fallback implementations of
|
|
meillo@121
|
3245 .Fu memmove()
|
|
meillo@121
|
3246 and
|
|
meillo@121
|
3247 .Fu strerror() ,
|
|
meillo@121
|
3248 although Peter Maydell had re-included them into nmh in 2008
|
|
meillo@121
|
3249 to support SunOS 4.
|
|
meillo@121
|
3250 Nevertheless, these functions are part of ANSI C.
|
|
meillo@121
|
3251 Systems that do not even provide full ANSI C support should not
|
|
meillo@121
|
3252 put a load on mmh.
|
|
meillo@121
|
3253 .Ci b067ff5c465a5d243ce5a19e562085a9a1a97215
|
|
meillo@121
|
3254 .P
|
|
meillo@121
|
3255 The
|
|
meillo@121
|
3256 .Fu copy()
|
|
meillo@121
|
3257 function copies the string in argument one to the location in two.
|
|
meillo@121
|
3258 In contrast to
|
|
meillo@121
|
3259 .Fu strcpy() ,
|
|
meillo@121
|
3260 it returns a pointer to the terminating null-byte in the destination area.
|
|
meillo@123
|
3261 The code was adjusted to replace
|
|
meillo@121
|
3262 .Fu copy()
|
|
meillo@123
|
3263 with
|
|
meillo@121
|
3264 .Fu strcpy() ,
|
|
meillo@121
|
3265 except within
|
|
meillo@121
|
3266 .Fu concat() ,
|
|
meillo@121
|
3267 where
|
|
meillo@121
|
3268 .Fu copy()
|
|
meillo@123
|
3269 was more convenient.
|
|
meillo@123
|
3270 Therefore, the definition of
|
|
meillo@121
|
3271 .Fu copy()
|
|
meillo@123
|
3272 was moved into the source file of
|
|
meillo@121
|
3273 .Fu concat()
|
|
meillo@123
|
3274 and its visibility is now limited to it.
|
|
meillo@121
|
3275 .Ci 552fd7253e5ee9e554c5c7a8248a6322aa4363bb
|
|
meillo@121
|
3276 .P
|
|
meillo@121
|
3277 The function
|
|
meillo@121
|
3278 .Fu r1bindex()
|
|
meillo@121
|
3279 had been a generalized version of
|
|
meillo@121
|
3280 .Fu basename()
|
|
meillo@121
|
3281 with minor differences.
|
|
meillo@121
|
3282 As all calls to
|
|
meillo@121
|
3283 .Fu r1bindex()
|
|
meillo@121
|
3284 had the slash (`/') as delimiter anyway,
|
|
meillo@121
|
3285 replacing
|
|
meillo@121
|
3286 .Fu r1bindex()
|
|
meillo@121
|
3287 with the more specific and better-named function
|
|
meillo@121
|
3288 .Fu basename()
|
|
meillo@121
|
3289 became desirable.
|
|
meillo@121
|
3290 Unfortunately, many of the 54 calls to
|
|
meillo@121
|
3291 .Fu r1bindex()
|
|
meillo@123
|
3292 depended on a special behavior,
|
|
meillo@121
|
3293 which differed from the POSIX specification for
|
|
meillo@121
|
3294 .Fu basename() .
|
|
meillo@121
|
3295 Hence,
|
|
meillo@121
|
3296 .Fu r1bindex()
|
|
meillo@121
|
3297 was kept but renamed to
|
|
meillo@123
|
3298 .Fu mhbasename() ,
|
|
meillo@123
|
3299 fixing the delimiter to the slash.
|
|
meillo@121
|
3300 .Ci 240013872c392fe644bd4f79382d9f5314b4ea60
|
|
meillo@121
|
3301 For possible uses of
|
|
meillo@121
|
3302 .Fu r1bindex()
|
|
meillo@121
|
3303 with a different delimiter,
|
|
meillo@121
|
3304 the ANSI C function
|
|
meillo@121
|
3305 .Fu strrchr()
|
|
meillo@121
|
3306 provides the core functionality.
|
|
meillo@121
|
3307 .P
|
|
meillo@121
|
3308 The
|
|
meillo@121
|
3309 .Fu ssequal()
|
|
meillo@121
|
3310 function \(en apparently for ``substring equal'' \(en
|
|
meillo@121
|
3311 was renamed to
|
|
meillo@121
|
3312 .Fu isprefix() ,
|
|
meillo@121
|
3313 because this is what it actually checks.
|
|
meillo@121
|
3314 .Ci c20b4fa14515c7ab388ce35411d89a7a92300711
|
|
meillo@121
|
3315 Its source file had included the following comments, no joke.
|
|
meillo@121
|
3316 .VS
|
|
meillo@121
|
3317 /*
|
|
meillo@121
|
3318 * THIS CODE DOES NOT WORK AS ADVERTISED.
|
|
meillo@121
|
3319 * It is actually checking if s1 is a PREFIX of s2.
|
|
meillo@121
|
3320 * All calls to this function need to be checked to see
|
|
meillo@121
|
3321 * if that needs to be changed. Prefix checking is cheaper, so
|
|
meillo@121
|
3322 * should be kept if it's sufficient.
|
|
meillo@121
|
3323 */
|
|
meillo@121
|
3324
|
|
meillo@121
|
3325 /*
|
|
meillo@121
|
3326 * Check if s1 is a substring of s2.
|
|
meillo@121
|
3327 * If yes, then return 1, else return 0.
|
|
meillo@121
|
3328 */
|
|
meillo@121
|
3329 VE
|
|
meillo@123
|
3330 Two months later, it was completely removed by replacing it with
|
|
meillo@123
|
3331 .Fu strncmp() .
|
|
meillo@123
|
3332 .Ci b0b1dd37ff515578cf7cba51625189eb34a196cb
|
|
meillo@121
|
3333
|
|
meillo@102
|
3334
|
|
meillo@102
|
3335
|
|
meillo@102
|
3336
|
|
meillo@133
|
3337
|
|
meillo@133
|
3338 .H2 "User Data Locations
|
|
meillo@133
|
3339 .P
|
|
meillo@133
|
3340 In nmh, a personal setup consists of the MH profile and the MH directory.
|
|
meillo@133
|
3341 The profile is a file named
|
|
meillo@133
|
3342 .Fn \&.mh_profile
|
|
meillo@133
|
3343 in the user's home directory.
|
|
meillo@133
|
3344 It contains the static configuration.
|
|
meillo@133
|
3345 It also contains the location of the MH directory in the profile entry
|
|
meillo@133
|
3346 .Pe Path .
|
|
meillo@133
|
3347 The MH directory contains the mail storage and is the first
|
|
meillo@133
|
3348 place to search for personal forms, scan formats, and similar
|
|
meillo@133
|
3349 configuration files.
|
|
meillo@133
|
3350 The location of the MH directory can be chosen freely by the user.
|
|
meillo@133
|
3351 The default and usual name is a directory named
|
|
meillo@133
|
3352 .Fn Mail
|
|
meillo@133
|
3353 in the home directory.
|
|
meillo@133
|
3354 .P
|
|
meillo@133
|
3355 The way MH data is splitted between profile and MH directory is a legacy.
|
|
meillo@133
|
3356 It is only sensible in a situation where the profile is the only
|
|
meillo@133
|
3357 configuration file.
|
|
meillo@133
|
3358 Why else should the mail storage and the configuration files be intermixed?
|
|
meillo@133
|
3359 They are different kinds of data:
|
|
meillo@133
|
3360 The data to be operated on and the configuration to change how
|
|
meillo@133
|
3361 tools operate.
|
|
meillo@133
|
3362 Splitting the configuration between the profile and the MH directory
|
|
meillo@133
|
3363 is bad.
|
|
meillo@133
|
3364 Merging the mail storage and the configuration in one directory is bad
|
|
meillo@133
|
3365 as well.
|
|
meillo@133
|
3366 As the mail storage and the configuration were not separated sensibly
|
|
meillo@133
|
3367 in the first place, I did it now.
|
|
meillo@133
|
3368 .P
|
|
meillo@133
|
3369 Personal mmh data is grouped by type, resulting in two distinct parts:
|
|
meillo@133
|
3370 The mail storage and the configuration.
|
|
meillo@133
|
3371 In mmh, the mail storage directory still contains all the messages,
|
|
meillo@133
|
3372 but, in exception of public sequences files, nothing else.
|
|
meillo@133
|
3373 In difference to nmh, the auxiliary configuration files are no longer
|
|
meillo@133
|
3374 located there.
|
|
meillo@133
|
3375 Therefore, the directory is no longer called the user's \fIMH directory\fP
|
|
meillo@133
|
3376 but his \fImail storage\fP.
|
|
meillo@133
|
3377 Its location is still user-chosen, with the default name
|
|
meillo@133
|
3378 .Fn Mail ,
|
|
meillo@133
|
3379 in the user's home directory.
|
|
meillo@133
|
3380 In mmh, the configuration is grouped together in
|
|
meillo@133
|
3381 the hidden directory
|
|
meillo@133
|
3382 .Fn \&.mmh
|
|
meillo@133
|
3383 in the user's home directory.
|
|
meillo@133
|
3384 This \fImmh directory\fP contains the context file, personal forms,
|
|
meillo@133
|
3385 scan formats, and the like, but also the user's profile, now named
|
|
meillo@133
|
3386 .Fn profile .
|
|
meillo@133
|
3387 The location of the profile is no longer fixed to
|
|
meillo@133
|
3388 .Fn $HOME/.mh_profile
|
|
meillo@133
|
3389 but to
|
|
meillo@133
|
3390 .Fn $HOME/.mmh/profile .
|
|
meillo@133
|
3391 Having both, the file
|
|
meillo@133
|
3392 .Fn $HOME/.mh_profile
|
|
meillo@133
|
3393 and the configuration directory
|
|
meillo@133
|
3394 .Fn $HOME/.mmh
|
|
meillo@133
|
3395 appeared to be inconsistent.
|
|
meillo@133
|
3396 The approach chosen for mmh is consistent, simple, and familiar to
|
|
meillo@133
|
3397 Unix users.
|
|
meillo@133
|
3398 .P
|
|
meillo@133
|
3399 MH allows users to have multiiple MH setups.
|
|
meillo@133
|
3400 Therefore, it is necessary to select a different profile.
|
|
meillo@133
|
3401 The profile is the single entry point to access the rest of a
|
|
meillo@133
|
3402 personal MH setup.
|
|
meillo@133
|
3403 In nmh, the environment variable
|
|
meillo@133
|
3404 .Ev MH
|
|
meillo@133
|
3405 could be used to specifiy a different profile.
|
|
meillo@133
|
3406 To operate in the same MH setup with a separate context,
|
|
meillo@133
|
3407 the
|
|
meillo@133
|
3408 .Ev MHCONTEXT
|
|
meillo@133
|
3409 environment variable could be used.
|
|
meillo@133
|
3410 This allows having own current folders and current messages in
|
|
meillo@133
|
3411 each terminal, for instance.
|
|
meillo@133
|
3412 In mmh, three environment variables are used.
|
|
meillo@133
|
3413 .Ev MMH
|
|
meillo@133
|
3414 overrides the default location of the mmh directory (\c
|
|
meillo@133
|
3415 .Fn .mmh ).
|
|
meillo@133
|
3416 .Ev MMHP
|
|
meillo@133
|
3417 and
|
|
meillo@133
|
3418 .Ev MMHC
|
|
meillo@133
|
3419 override the paths to the profile and context files, respectively.
|
|
meillo@133
|
3420 This approach allows the set of personal configuration files to be chosen
|
|
meillo@133
|
3421 independently from the profile, context, and mail storage.
|
|
meillo@133
|
3422 .P
|
|
meillo@133
|
3423 The separation of the files by type is sensible and convenient.
|
|
meillo@133
|
3424 The new approach has no functional disadvantages,
|
|
meillo@133
|
3425 as every setup I can imagine can be implemented with both approaches,
|
|
meillo@133
|
3426 possibly even easier with the new approach.
|
|
meillo@133
|
3427 The main achievement of the change is the clear and sensible split
|
|
meillo@133
|
3428 between mail storage and configuration.
|
|
meillo@133
|
3429
|
|
meillo@133
|
3430
|
|
meillo@133
|
3431
|
|
meillo@133
|
3432
|
|
meillo@133
|
3433
|
|
meillo@118
|
3434 .H2 "Modularization
|
|
meillo@118
|
3435 .P
|
|
meillo@123
|
3436 The source code of the mmh tools is located in the
|
|
meillo@122
|
3437 .Fn uip
|
|
meillo@123
|
3438 (``user interface programs'') directory.
|
|
meillo@123
|
3439 Each tools has a source file with the same name.
|
|
meillo@122
|
3440 For example,
|
|
meillo@122
|
3441 .Pn rmm
|
|
meillo@122
|
3442 is built from
|
|
meillo@122
|
3443 .Fn uip/rmm.c .
|
|
meillo@123
|
3444 Some source files are used for multiple programs.
|
|
meillo@122
|
3445 For example
|
|
meillo@122
|
3446 .Fn uip/scansbr.c
|
|
meillo@123
|
3447 is used for both,
|
|
meillo@122
|
3448 .Pn scan
|
|
meillo@122
|
3449 and
|
|
meillo@122
|
3450 .Pn inc .
|
|
meillo@122
|
3451 In nmh, 49 tools were built from 76 source files.
|
|
meillo@123
|
3452 This is a ratio of 1.6 source files per program.
|
|
meillo@123
|
3453 32 programs depended on multiple source files;
|
|
meillo@123
|
3454 17 programs depended on one source file only.
|
|
meillo@122
|
3455 In mmh, 39 tools are built from 51 source files.
|
|
meillo@123
|
3456 This is a ratio of 1.3 source files per program.
|
|
meillo@123
|
3457 18 programs depend on multiple source files;
|
|
meillo@123
|
3458 21 programs depend on one source file only.
|
|
meillo@123
|
3459 (These numbers and the ones in the following text ignore the MH library
|
|
meillo@123
|
3460 as well as shell scripts and multiple names for the same program.)
|
|
meillo@122
|
3461 .P
|
|
meillo@123
|
3462 Splitting the source code of a large program into multiple files can
|
|
meillo@122
|
3463 increase the readability of its source code.
|
|
meillo@124
|
3464 Most of the mmh tools, however, are simple and straight-forward programs.
|
|
meillo@122
|
3465 With the exception of the MIME handling tools,
|
|
meillo@122
|
3466 .Pn pick
|
|
meillo@122
|
3467 is the largest tools.
|
|
meillo@122
|
3468 It contains 1\|037 lines of source code (measured with
|
|
meillo@122
|
3469 .Pn sloccount ), excluding the MH library.
|
|
meillo@122
|
3470 Only the MIME handling tools (\c
|
|
meillo@122
|
3471 .Pn mhbuild ,
|
|
meillo@122
|
3472 .Pn mhstore ,
|
|
meillo@122
|
3473 .Pn show ,
|
|
meillo@122
|
3474 etc.)
|
|
meillo@122
|
3475 are larger.
|
|
meillo@122
|
3476 Splitting programs with less than 1\|000 lines of code into multiple
|
|
meillo@123
|
3477 source files seldom leads to better readability.
|
|
meillo@123
|
3478 For such tools, splitting makes sense
|
|
meillo@122
|
3479 when parts of the code are reused in other programs,
|
|
meillo@122
|
3480 and the reused code fragment is not general enough
|
|
meillo@122
|
3481 for including it in the MH library,
|
|
meillo@124
|
3482 or, if the code has dependencies on a library that only few programs need.
|
|
meillo@122
|
3483 .Fn uip/packsbr.c ,
|
|
meillo@122
|
3484 for instance, provides the core program logic for the
|
|
meillo@122
|
3485 .Pn packf
|
|
meillo@122
|
3486 and
|
|
meillo@122
|
3487 .Pn rcvpack
|
|
meillo@122
|
3488 programs.
|
|
meillo@122
|
3489 .Fn uip/packf.c
|
|
meillo@122
|
3490 and
|
|
meillo@122
|
3491 .Fn uip/rcvpack.c
|
|
meillo@122
|
3492 mainly wrap the core function appropriately.
|
|
meillo@122
|
3493 No other tools use the folder packing functions.
|
|
meillo@123
|
3494 As another example,
|
|
meillo@123
|
3495 .Fn uip/termsbr.c
|
|
meillo@123
|
3496 provides termcap support, which requires linking with a termcap or
|
|
meillo@123
|
3497 curses library.
|
|
meillo@123
|
3498 Including
|
|
meillo@123
|
3499 .Fn uip/termsbr.c
|
|
meillo@123
|
3500 into the MH library would require every program to be linked with
|
|
meillo@123
|
3501 termcap or curses, although only few of the programs require it.
|
|
meillo@122
|
3502 .P
|
|
meillo@122
|
3503 The task of MIME handling is complex enough that splitting its code
|
|
meillo@122
|
3504 into multiple source files improves the readability.
|
|
meillo@122
|
3505 The program
|
|
meillo@122
|
3506 .Pn mhstore ,
|
|
meillo@122
|
3507 for instance, is compiled out of seven source files with 2\|500
|
|
meillo@122
|
3508 lines of code in summary.
|
|
meillo@122
|
3509 The main code file
|
|
meillo@122
|
3510 .Fn uip/mhstore.c
|
|
meillo@123
|
3511 consists of 800 lines; the other 1\|700 lines of code are reused in
|
|
meillo@123
|
3512 other MIME handling tools.
|
|
meillo@123
|
3513 It seems to be worthwhile to bundle the generic MIME handling code into
|
|
meillo@123
|
3514 a MH-MIME library, as a companion to the MH standard library.
|
|
meillo@122
|
3515 This is left open for the future.
|
|
meillo@122
|
3516 .P
|
|
meillo@123
|
3517 The work already done, focussed on the non-MIME tools.
|
|
meillo@122
|
3518 The amount of code compiled into each program was reduced.
|
|
meillo@123
|
3519 This eases the understanding of the code base.
|
|
meillo@122
|
3520 In nmh,
|
|
meillo@122
|
3521 .Pn comp
|
|
meillo@122
|
3522 was built from six source files:
|
|
meillo@122
|
3523 .Fn comp.c ,
|
|
meillo@122
|
3524 .Fn whatnowproc.c ,
|
|
meillo@122
|
3525 .Fn whatnowsbr.c ,
|
|
meillo@122
|
3526 .Fn sendsbr.c ,
|
|
meillo@122
|
3527 .Fn annosbr.c ,
|
|
meillo@122
|
3528 and
|
|
meillo@122
|
3529 .Fn distsbr.c .
|
|
meillo@122
|
3530 In mmh, it builds from only two:
|
|
meillo@122
|
3531 .Fn comp.c
|
|
meillo@122
|
3532 and
|
|
meillo@122
|
3533 .Fn whatnowproc.c .
|
|
meillo@123
|
3534 In nmh's
|
|
meillo@123
|
3535 .Pn comp ,
|
|
meillo@123
|
3536 the core function of
|
|
meillo@122
|
3537 .Pn whatnow ,
|
|
meillo@122
|
3538 .Pn send ,
|
|
meillo@122
|
3539 and
|
|
meillo@122
|
3540 .Pn anno
|
|
meillo@123
|
3541 were compiled into
|
|
meillo@122
|
3542 .Pn comp .
|
|
meillo@123
|
3543 This saved the need to execute these programs with
|
|
meillo@122
|
3544 .Fu fork()
|
|
meillo@122
|
3545 and
|
|
meillo@122
|
3546 .Fu exec() ,
|
|
meillo@122
|
3547 two expensive system calls.
|
|
meillo@122
|
3548 Whereis this approach improved the time performance,
|
|
meillo@122
|
3549 it interweaved the source code.
|
|
meillo@122
|
3550 Core functionalities were not encapsulated into programs but into
|
|
meillo@122
|
3551 function, which were then wrapped by programs.
|
|
meillo@122
|
3552 For example,
|
|
meillo@122
|
3553 .Fn uip/annosbr.c
|
|
meillo@122
|
3554 included the function
|
|
meillo@122
|
3555 .Fu annotate() .
|
|
meillo@122
|
3556 Each program that wanted to annotate messages, included the source file
|
|
meillo@123
|
3557 .Fn uip/annosbr.c
|
|
meillo@123
|
3558 and called
|
|
meillo@123
|
3559 .Fu annotate() .
|
|
meillo@123
|
3560 Because the function
|
|
meillo@123
|
3561 .Fu annotate()
|
|
meillo@123
|
3562 was used like the tool
|
|
meillo@123
|
3563 .Pn anno ,
|
|
meillo@123
|
3564 it had seven parameters, reflecting the command line switches of the tool.
|
|
meillo@122
|
3565 When another pair of command line switches was added to
|
|
meillo@122
|
3566 .Pn anno ,
|
|
meillo@122
|
3567 a rather ugly hack was implemented to avoid adding another parameter
|
|
meillo@122
|
3568 to the function.
|
|
meillo@122
|
3569 .Ci d9b1d57351d104d7ec1a5621f090657dcce8cb7f
|
|
meillo@122
|
3570 .P
|
|
meillo@122
|
3571 Separation simplifies the understanding of program code
|
|
meillo@122
|
3572 because the area influenced by any particular statement is smaller.
|
|
meillo@122
|
3573 The separating on the program-level is more strict than the separation
|
|
meillo@122
|
3574 on the function level.
|
|
meillo@122
|
3575 In mmh, the relevant code of
|
|
meillo@122
|
3576 .Pn comp
|
|
meillo@122
|
3577 comprises the two files
|
|
meillo@122
|
3578 .Fn uip/comp.c
|
|
meillo@122
|
3579 and
|
|
meillo@122
|
3580 .Fn uip/whatnowproc.c ,
|
|
meillo@123
|
3581 together 210 lines of code.
|
|
meillo@122
|
3582 In nmh,
|
|
meillo@122
|
3583 .Pn comp
|
|
meillo@122
|
3584 comprises six files with 2\|450 lines.
|
|
meillo@123
|
3585 Not all of the code in these six files was actually used by
|
|
meillo@122
|
3586 .Pn comp ,
|
|
meillo@123
|
3587 but the code reader needed to read all of the code first to know which
|
|
meillo@123
|
3588 parts were used.
|
|
meillo@122
|
3589 .P
|
|
meillo@123
|
3590 As I have read a lot in the code base during the last two years,
|
|
meillo@123
|
3591 I learned about the easy and the difficult parts.
|
|
meillo@123
|
3592 Code is easy to understand if:
|
|
meillo@123
|
3593 .BU
|
|
meillo@123
|
3594 The influenced code area is small
|
|
meillo@123
|
3595 .BU
|
|
meillo@124
|
3596 The boundaries are strictly defined
|
|
meillo@123
|
3597 .BU
|
|
meillo@123
|
3598 The code is written straight-forward
|
|
meillo@123
|
3599 .P
|
|
meillo@123
|
3600 .\" XXX move this paragraph somewhere else?
|
|
meillo@123
|
3601 Reading
|
|
meillo@122
|
3602 .Pn rmm 's
|
|
meillo@122
|
3603 source code in
|
|
meillo@122
|
3604 .Fn uip/rmm.c
|
|
meillo@122
|
3605 is my recommendation for a beginner's entry point into the code base of nmh.
|
|
meillo@122
|
3606 The reasons are that the task of
|
|
meillo@122
|
3607 .Pn rmm
|
|
meillo@122
|
3608 is straight forward and it consists of one small source code file only,
|
|
meillo@122
|
3609 yet its source includes code constructs typical for MH tools.
|
|
meillo@122
|
3610 With the introduction of the trash folder in mmh,
|
|
meillo@122
|
3611 .Pn rmm
|
|
meillo@122
|
3612 became a bit more complex, because it invokes
|
|
meillo@122
|
3613 .Pn refile .
|
|
meillo@122
|
3614 Still, it is a good example for a simple tool with clear sources.
|
|
meillo@122
|
3615 .P
|
|
meillo@122
|
3616 Understanding
|
|
meillo@122
|
3617 .Pn comp
|
|
meillo@122
|
3618 requires to read 210 lines of code in mmh, but ten times as much in nmh.
|
|
meillo@123
|
3619 Due to the aforementioned hack in
|
|
meillo@122
|
3620 .Pn anno
|
|
meillo@122
|
3621 to save the additional parameter, information passed through the program's
|
|
meillo@122
|
3622 source base in obscure ways.
|
|
meillo@123
|
3623 Thus, understanding
|
|
meillo@122
|
3624 .Pn comp ,
|
|
meillo@123
|
3625 required understanding the inner workings of
|
|
meillo@122
|
3626 .Fn uip/annosbr.c
|
|
meillo@122
|
3627 first.
|
|
meillo@123
|
3628 To be sure to fully understand a program, its whole source code needs
|
|
meillo@122
|
3629 to be examined.
|
|
meillo@123
|
3630 Not doing so is a leap of faith, assuming that the developers
|
|
meillo@122
|
3631 have avoided obscure programming techniques.
|
|
meillo@122
|
3632 By separating the tools on the program-level, the boundaries are
|
|
meillo@122
|
3633 clearly visible and technically enforced.
|
|
meillo@122
|
3634 The interfaces are calls to
|
|
meillo@122
|
3635 .Fu exec()
|
|
meillo@122
|
3636 rather than arbitrary function calls.
|
|
meillo@123
|
3637 .P
|
|
meillo@123
|
3638 But the real problem is another:
|
|
meillo@123
|
3639 Nmh violates the golden ``one tool, one job'' rule of the Unix philosophy.
|
|
meillo@123
|
3640 Understanding
|
|
meillo@122
|
3641 .Pn comp
|
|
meillo@123
|
3642 requires understanding
|
|
meillo@123
|
3643 .Fn uip/annosbr.c
|
|
meillo@123
|
3644 and
|
|
meillo@123
|
3645 .Fn uip/sendsbr.c
|
|
meillo@123
|
3646 because
|
|
meillo@123
|
3647 .Pn comp
|
|
meillo@123
|
3648 does annotate and send messages.
|
|
meillo@123
|
3649 In nmh, there surely exists the tool
|
|
meillo@122
|
3650 .Pn send ,
|
|
meillo@123
|
3651 which does (almost) only send messages.
|
|
meillo@123
|
3652 But
|
|
meillo@122
|
3653 .Pn comp
|
|
meillo@123
|
3654 and
|
|
meillo@122
|
3655 .Pn repl
|
|
meillo@122
|
3656 and
|
|
meillo@122
|
3657 .Pn forw
|
|
meillo@122
|
3658 and
|
|
meillo@122
|
3659 .Pn dist
|
|
meillo@122
|
3660 and
|
|
meillo@122
|
3661 .Pn whatnow
|
|
meillo@122
|
3662 and
|
|
meillo@123
|
3663 .Pn viamail ,
|
|
meillo@123
|
3664 they all (!) have the same message sending function included, too.
|
|
meillo@123
|
3665 In result,
|
|
meillo@123
|
3666 .Pn comp
|
|
meillo@123
|
3667 sends messages without using
|
|
meillo@123
|
3668 .Pn send .
|
|
meillo@123
|
3669 The situation is the same as if
|
|
meillo@123
|
3670 .Pn grep
|
|
meillo@123
|
3671 would page without
|
|
meillo@123
|
3672 .Pn more
|
|
meillo@123
|
3673 just because both programs are part of the same code base.
|
|
meillo@123
|
3674 .P
|
|
meillo@122
|
3675 The clear separation on the surface \(en the toolchest approach \(en
|
|
meillo@123
|
3676 is violated on the level below.
|
|
meillo@122
|
3677 This violation is for the sake of time performance.
|
|
meillo@122
|
3678 On systems where
|
|
meillo@122
|
3679 .Fu fork()
|
|
meillo@122
|
3680 and
|
|
meillo@122
|
3681 .Fu exec()
|
|
meillo@122
|
3682 are expensive, the quicker response might be noticable.
|
|
meillo@124
|
3683 In the old times, sacrificing readability and conceptional beauty for
|
|
meillo@124
|
3684 speed might even have been a must to prevent MH from being unusably slow.
|
|
meillo@122
|
3685 Whatever the reasons had been, today they are gone.
|
|
meillo@123
|
3686 No longer should we sacrifice readability or conceptional beauty.
|
|
meillo@122
|
3687 No longer should we violate the Unix philosophy's ``one tool, one job''
|
|
meillo@122
|
3688 guideline.
|
|
meillo@123
|
3689 No longer should we keep speed improvements that became unnecessary.
|
|
meillo@122
|
3690 .P
|
|
meillo@123
|
3691 Therefore, mmh's
|
|
meillo@123
|
3692 .Pn comp
|
|
meillo@123
|
3693 does no longer send messages.
|
|
meillo@123
|
3694 In mmh, different jobs are divided among separate programs that
|
|
meillo@122
|
3695 invoke each other as needed.
|
|
meillo@123
|
3696 In consequence,
|
|
meillo@123
|
3697 .Pn comp
|
|
meillo@123
|
3698 invokes
|
|
meillo@123
|
3699 .Pn whatnow
|
|
meillo@123
|
3700 which thereafter invokes
|
|
meillo@123
|
3701 .Pn send .
|
|
meillo@123
|
3702 The clear separation on the surface is maintained on the level below.
|
|
meillo@123
|
3703 Human users and the tools use the same interface \(en
|
|
meillo@123
|
3704 annotations, for example, are made by invoking
|
|
meillo@123
|
3705 .Pn anno ,
|
|
meillo@123
|
3706 no matter if requested by programs or by human beings.
|
|
meillo@123
|
3707 The decrease of tools built from multiple source files and thus
|
|
meillo@123
|
3708 the decrease of
|
|
meillo@123
|
3709 .Fn uip/*sbr.c
|
|
meillo@123
|
3710 files confirm the improvement.
|
|
meillo@123
|
3711 .P
|
|
meillo@123
|
3712 One disadvantage needs to be taken with this change:
|
|
meillo@123
|
3713 The compiler can no longer check the integrity of the interfaces.
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meillo@123
|
3714 By changing the command line interfaces of tools, it is
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meillo@123
|
3715 the developer's job to adjust the invocations of these tools as well.
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meillo@123
|
3716 As this is a manual task and regression tests, which could detect such
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meillo@124
|
3717 problems, are not available yet, it is prone to errors.
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meillo@123
|
3718 These errors will not be detected at compile time but at run time.
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meillo@123
|
3719 Installing regression tests is a task left to do.
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|
meillo@123
|
3720 In the best case, a uniform way of invoking tools from other tools
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meillo@123
|
3721 can be developed to allow automated testing at compile time.
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